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complete notes of chemistry class nine

CHEMISTRY COMPLETE NOTES OF IX


Chapter : INTRODUCTION TO CHEMISTRY

Chemistry
The branch of science which deals with the composition and properties of matter, changes in matter and the laws or principles which govern these changes is called Chemistry.
Branches of Chemistry
Physical Chemistry
The branch of chemistry which deals with the physical properties and physical behavior of material things is called physical chemistry.
Inorganic Chemistry
The study of all elements and their compounds except carbon is called inorganic chemistry.
Organic Chemistry
The branch of chemistry in which we study the compounds of carbon is called organic chemistry.
Analytical Chemistry
The branch of chemistry which discusses the analytical methods for getting information about chemical compounds and chemical processes is called analytical chemistry.
Biochemistry
The study of chemical compounds present in living things is called biochemistry.
Industrial Chemistry
The application of chemical knowledge in technology and industry and the preparation of industrial products are called industrial chemistry


Steps Involved in Getting Information in the Scientific Method
Science is not only an integrated knowledge of physical and biological phenomena but also the methodology through which this knowledge is gathered. The process of scientific discoveries is a cyclic process.
In science the facts are gathered through observations and experiments and then theories or law are deduced. The scientific method include following four steps:
1. Observation
2. Inference
3. Prediction
4. Experiment
Observation
The observations are made by the five senses of man. Men made equipments are also used for making observations. For example microscope is used for observing minute objects. Thermometer is used to measure temperature. Sensitive balance is used to determine the mass of a very light object. The capacity of man made instruments is also limited. But it can be improved by improving technology. Thus better and more reliable information are given to the scientists who produce better result. Information acquired through careful observations are called facts. These facts are foundation of scientific knowledge.
Inference
The facts gathered through observations are carefully arranged and properly classified. Correlating the knowledge thus acquired with previous knowledge, we try to think of a tentative solution to explain the observed phenomenon. The tentative solution is called hypothesis. The validity of this hypothesis is tested through the results obtained from experiments. The results are discussed by the scientists and the hypothesis is accepted or rejected. The accepted hypothesis then takes the form of theory. A theory when repeatedly gives the same results after experimentation and gives correct explanation of the scientific facts becomes a law or principle.
A theory remains valid until contrary informations are given on the basis of experimentation. Thus a hypothesis requires experimental support. But Avogadro's hypothesis has been accepted as law without any experimental support.
Prediction
Facts, theories and laws which are deduced from observation can help in deducing more facts and phenomenon. This process is called prediction.
Experiment
An experiment is an integrated activity, which is performed under suitable conditions with specially designed instruments to get the required information. Such information is used to test the validity of the hypothesis. If a hypothesis is proved correct. It increases the reliability of known facts. If it is proved wrong, it stil can give information which can be used to deduce other results.


Chemistry and Society
Chemistry has played important role for well being of mankind in the form of food, clothing, shelter, medical treatment and chemical fertilizers, crops protected by insecticides, refined food and production of artificial fiber. Production of cement, iron bricks, glass, paint etc are all due to chemistry.
The hazards of chemistry are so vast that no aspect of human life has remained unaffected. The smoke coming from chimneys of chemial industries and from vehicles pollute the air. It is very dangerous to breath in that air. Similarly waste water from industry, pollute canals, rivers and has bad effect on land. Excessive chemical spray on plants also has bad effect.



Chapter : CHEMICAL COMBINATION & CHEMICAL EQUATION


Laws of Chemical Combinations
There are four laws of chemical combinations these laws explained the general feature of chemical change. These laws are:
1. Law of Conservation of Mass
2. Law of Definite Proportions
3. Law of Multiple Proportions
4. Law Reciprocal Proportions

Antoine Lavoiser has rejected the worn out ideas about the changes that take place during a chemical reaction. He made careful quantitative measurements in chemical reactions and established that mass is neither created nor nor destroyed in a chemical change.

Law of Conservation of Mass
Statement
It is presented by Lavoiser. It is defined as:
"Mass is neither created nor destroyed during a chemical reaction but it only changes from one form to another form."
In a chemical reaction, reactants are converted to products. But the total mass of the reactants and products remains the same. The following experiment easily proves law of conservation of mass.
Practical Verification (Landolt Experiment)
German chemist H. Landolt, studied about fifteen different chemical reactions with a great skill, to test the validity of the law of conservation of mass. For this, he took H.shaped tube and filled the two limbs A and B, with silver nitrate (AgNO3) in limb A and Hydrochloric Acid (HCl) in limb B. The tube was sealed so that material could not escape outside. The tube was weighed initially in a vertical position so that the solution should not intermix with each other. The reactant were mixed by inverting and shaking the tube. The tube was weighed after mixing (on the formation of white precipitate of AgCl). He observed that weight remains same.
HCl + AgNO3 ----------> AgCl + NaNO3

Law of Definite Proportions
Statement
It is presented by Proust. It is defined as:
"When different elements combine to give a pure compound, the ratio between the masses of these elements will always remain the same."
Proust proved experimentally that compound obtained from difference source will always contain same elements combined together in fixed proportions.
Example
Water can be obtained from different sources such as river, ocean, well, canal, tube well, rain or by the chemical combination of hydrogen and oxygen. If different samples of water are analyzed, it will have two elements, hydrogen and oxygen and the ratio between their mass is 1:8.

Law of Multiple Proportions
Statement
This law is defined as:
"When two elements combine to give more than one compounds, the different masses of one element, which will combine with the fixed mass of other element, will be in simple whole number ratio."
Two different elements can combine to form more than one compound. They can do so by combining in different ratios to give different compounds.
Example
Hydrogen and oxygen combine with one another to form water (H2O) and hydrogen peroxide (H2O2). In water and hydrogen oxide 2 g of hydrogen combine with 16g and 32g of oxygen respectively. According to law of multiple proportions, the different masses of oxygen (16g and 32g) which have reacted with fixed mass (2g) of hydrogen will have a simple ratio between each other i.e. 16:32 or 1:2. It means that hydrogen peroxide contains double the number of oxygen atoms than water. This law proves this point of Dalton's Atomic Theory that atoms do not break in a chemical reaction.

Law of Reciprocal Proportions
Statement
This law is defined as:
"When two element A, B combine separately, with the mixed mass of the third element E, the ratio in which these elements combine with E is either the same or simple multiple of the ratio in which A and B combine with each other."
Example
Hydrogen and Nitrogen separately combine to form ammonia (NH3) and dinitrogen oxide (N2O), in these compounds, fixed mass of nitrogen is 14g and combines with 8 g of oxygen and 3 g of hydrogen. The ratio between the mass of oxygen and hydrogen is 8:3. Hydrogen and oxygen also combine with one another to form water (H2O). The ratio between hydrogen and oxygen in water is 16:2. These ratios are not same. Let us observe whether these ratios are simple multiple to each other or not following mathematical operation is carried out.
8:3 ::16:2
8/3 : 16/2
or
8/3 x 2/16
or
1/3 => 1:3

Definitions
Atomic Mass
The mass of an atom of the element relative to the mass of some reference or standard element is called atomic mass. Atoms are very small particles. They have very small mass. If the masses of atoms were to be expressed in gram. It is a very big unit for this very tiny object. Then it was decided by the chemists that masses of the atoms were to be found after comparing with mass to some standard form.
Hydrogen being the lightest element is taken as standard. The mass of the hydrogen atom taken as one.
The atomic mass could be defined as
"Atomic mass of an element is the mass of an atom of that element as compared to the mass of an atom of hydrogen taken as one."
Example
The atomic mass of sodium is 23. It means that an atom of sodium is 23 times heavier than hydrogen atom. Similarly atomic mass of oxygen is 16. It means that an atom of oxygen is 16 times heaviest than that of hydrogen.

Atom
The smallest particle of an element which cannot exist independently and take part in a chemical reaction is known as Atom.
Examples
Hexogen(H), Carbon (C), Sodium (Na), Gold (Au) etc.

Molecule
The particle of a substance (Element or Compound) which can exist independently and show all the properties of that substance is called molecule.
Atoms of the same or different elements react with each other and form molecule.
Atoms of some elements can exist independently, since they have property of molecule so they are called mono atomic molecule.
Examples
Examples of Molecules of the elements are Hydrogen (H2). Nitrogen (N2), Sulphur (S8) etc.
Molecules of different elements are called compounds. For example HCl, H2O, CH4 etc.

Valency
The combining capacity of all elements with other elements is called valency.
Example
H = 1
C = 4
Al = 3
Mg = 2
Na = 1

Chemical Formula
"A brief name used for full chemical name at a compound is called Chemical Formula."
A chemical formula is used to represent an element or a compound in terms of symbols. It also represents the number and type of atoms of elements present in the smallest unit of that substance.
Example
The chemical formula of hydrogen sulphide is H2S. It shows two types of elements (H and S) and number of atoms of element (2H and 1S). Similarly the formula of NaCl show number and type of different atoms present in its smallest unit.

Empirical Formula
"The formula which shows the minimum (simple) ratio between atoms present in a compound is known as Empirical Formula."
Example
For example the empirical formula of hydrogen peroxide is HO that of water is H2O and benzene is CH.

Molecular Formula
The formula of an element or a compound which represents the actual number of atoms present in the molecule of these substances is called molecular formula.
Example
Water, Hydrogen Peroxide, Ethylene Benzene and Sulphur have molecular formula H2O, H2O2, C2H4, C6H6 and S8 respectively.
Molecular Mass
Molecular mass of an element or a compound is defined as the mass of its molecule relative to 1/12th of the mass of C-12. It is the sum of the atomic masses of all the atoms presents in its molecular formula.
Example
Molecular mass of water (H2O) = 2 + 16 = 18 a.m.u
Mass of hydrogen sulphide (H2S) = 2 + 32 = 34 a.m.u

Formula Mass
Formula mass of a compound is the mass of its formula unit relative to 1/12th of the mass of C-12.
Example
Formula mass of Sodium Chloride NaCl = 23 + 35.5 = 58.5 a.m.u
Formula mass of Calcium Chloride CaCl2 = 40 + 35.5x2 = 111a.m.u

Molar Mass
The mass of one mole of a substance is called molar mass.
Example
1 mole of Hydrogen atom (H) = 1.008g
1 mole of Hydrogen molecule (H2) = 2.016g
Thus mass of substance is related to the particles by mole.

Chemical Reaction
A chemical change in which reactants are converted to products is called chemical reaction.
Zn + 2HCl --------> ZnCl2 + H2
The fact that a chemical reaction is taking place can be inferred from the following observation.
1. Evolution of a gas
2. Change in colour
3. Change in temperature.
4. Emission of light.

Types of Chemical Reaction
The chemical reaction is classified into following types:
1. Displacement Reaction
The reaction in which an atom or group of atoms is displaced by another atom or group of atoms in a compound is called displacement reaction.
Fe + CuO ---------> Cu + FeO
2. Double Displacement Reactions
The reactions in which reacting substances exchange their radicals or ions are double displacement reaction. Insoluble salts are formed by mixing soluble salts.
3. Addition Reactions
When two different compounds or elements react together to give only one confound, the reaction will be called addition reaction.
2Mg + O2 --------> 2MgO
4. Decomposition Reaction
The reaction in which some compounds may decompose into elements or simpler compounds on heating is called decomposition reaction.
CaCO3 ---------> CaO + CO2 (Heat)

Chemical Equation
Symbolic representation of chemical change in terms of symbols and formulae is called Chemical Equation.
Method of Equation Writing
A chemical equation can be written as follows:
1. Write the formulae and symbols of the reactants on the left hand side.
2. Write the formulae and sympols of the products on the right hand side.
3. Separate the reactants and products by an arrow which is directed towards the products.
Characteristics of Chemical Equation
1. Chemical equation must be representative of a chemical reaction.
2. It should represent molar quantities.
3. It should be balanced in terms of atoms/molecules of reactants and products.
Reactants
Those substances, which react together in a chemical reaction, are called reactants.
Zn + 2HCl ------> ZnCl2 + H2
In the above reaction Zn and HCl are the reactants.
Products
Those substances, which are formed in a chemical reaction, are called products.
Zn + 2HCl ------> ZnCl2 + H2
In the above reaction, ZnCl2 and H2 are products.
Information obtained from a Chemical Equation
1. A balanced equation indicates that which reactant undergo chemical change. It indicates that which products are formed.
2. It indicates that how many moles of reactants under go chemical change. It indicates that how many moles of products are formed.
Why are Chemical Equations Balanced
A chemical equation must be balanced in order to satisfy the law of conservation of matter, which states that matter can neither be created nor be destroyed during a chemical reaction.



Chapter : ATOMIC STRUCTURE


Dalton's Atomic Theory
The important postulates of Dalton's atomic theory are:
1. All elements are composed of atoms. Atom is too small so that it could not be divided into further simpler components.
2. Atom cannot be destroyed or produced.
3. Atoms of an element are similar in all respects. They have same mass and properties.
4. Atoms of different elements combine in a definite simple ratio to produce compounds.

Discovery of Electron
A discharge tube is a glass tube. It has two electrode, a source of electric current and a vacuum pump.
(Diagram)
Sir William Crooks (1895 performed experiments by passing electric current through gas in the discharge tube at very low pressure. He observed that at 10-4 (-4 is power to 10) atmosphere pressure, shining rays are emitted from cathode. These rays were named cathode rays. Cathode rays are material particles as they have mass and momentum.
Properties of Cathode Rays
The properties of these particles are given below:
1. These particles are emitted from cathode surface and move in straight line.
2. The temperature of the object rises on which they fall.
3. They produce shadow of opaque object placed in their path.
4. These particles are deflected in electric and magnetic fields.
5. These particles are deflected towards positive plate of electric field.

Discovery of Proton
Gold Stein (1886) observed that in addition to the cathode rays, another type of rays were present in the discharge tube. These rays travel in a direction opposite to cathode rays. These rays were named positive rays. By using perforated cathode in the discharge tube the properties of these rays can be studied. Positive rays are also composed of metered particles. The positive rays are not emitted from anode. They are produced by the ionization of residual gas molecules in the discharge tube. When cathode rays strike with gas molecule, electrons are removed and positive particles are produced.
Properties of Positive Rays
1. They are deflected towards negative plate of electric field. Therefore these rays carry positive charge.
2. The mass of positive rays is equal to the mass of the gas enclosed in the discharge tube.
3. The minimum mass of positive particles is equal to the mass of hydrogen ion (H+). These positive ions are called Protons.
4. The charge on proton is equal to +1.602x10-19 Coulomb. (-19 is power of 10)

Natural Radioactivity
The phenomenon in which certain elements emit radiation which can cause fogging of photographic plate is called natural radioactivity. The elements which omit these rays are called radioactive elements like Uranium, Thorium, Radium etc. There are about 40 radioactive elements. Henri Bequrel (1896) discovered radioactivity.Madam Curei also has valuable contribution in this field.
In natural radioactivity nuclei of elements are broken and element converted to other elements. Natural radioactivity is nuclear property of the elements.
Alpha Rays
1. They are helium nuclei. They are doubly positively charged, He2+.
2. They move with speed equal to the 1/10th of the velocity of the light.
3. They cannot pass through thick-metal foil.
4. They are very good ionizer of a gas.
5. They affect the photographic plate.
Beta Rays
1. They are negatively charged.
2. They move with the speed equal to the velocity of light.
3. They can pass through a few millimeter thick metal sheets.
4. They are good ionizer of a gas.
5. They can affect the photographic plate.
Gamma Rays
1. They are electromagnetic radiations.
2. They travel with speed equal to velocity of light.
3. They carry no charge.
4. They have high penetration power than alpha and beta rays.
5. They are weak ionizer of gas.

Rutherford Experiment and Discovery of Nucleus
Lord Rutherford (1911) and his coworkers performed an experiment. They bombarded a very thin, gold fail with Alpha particles from a radioactive source. They observed that most of the particles passed straight through the foil undeflected. But a few particles were deflected at different angles. One out of 4000 Alpha particles was deflected at an angle greater than 150.
(Diagram)
Conclusion
Following conclusions were drawn from the Rutherford's Alpha Particles scattering experiment.
1. The fact that majority of the particles went through the foil undeflected shows that most of the space occupied by an atom is empty.
2. The deflection of a few particles over a wide angle of 150 degrees shows that these particles strike with heavy body having positive charge.
3. The heavy positively charged central part of the atom is called nucleus.
4. Nearly all of the mass of atom is concentrated in the nucleus.
5. The size of the nucleus is very small as compared with the size of atom.
Defects of Rutherford Model
Rutherford model of an atom resembles our solar system. It has following defects:
1. According to classical electromagnetic theory, electron being charged body will emit energy continuously. Thus the orbit of the revolving electron becomes smaller and smaller until it would fall into the nucleus and atomic structure would collapse.
2. If revolving electron emits energy continuously then there should be a continuous spectrum but a line spectrum is obtained.
(Diagram)

Bohr's Atomic Model
Neil Bohr (1913) presented a model of atom which has removed the defects of Rutherford Model. This model was developed for hydrogen atom which has only proton in the nucleus and one electron is revolving around it.
Postulates of Bohr's Atomic Model
The main postulates of Bohr's Model are given below:
1. Electrons revolve around the nucleus in a fixed orbit.
2. As long as electron revolves in a fixed orbit it does not emit and absorb energy. Hence energy of electron remains constant.
3. The orbit nearest to the nucleus is the first orbit and has lowest energy. When an electron absorbs energy it jumps from lower energy orbit to higher energy orbit. Energy is emitted in the form of radiations, when an electron jumps from higher energy orbit to lower energy orbit. The unit of energy emitted in the form of radiations is called quantum. It explains the formation of atomic spectrum.
4. The change in energy is related with the quantum of radiation by the equation :
E2 - E1 = hv
where
E1 = Energy of first orbit
E2 = Energy of the second orbit
h = Planck's constant
v = Frequency of radiation

Atomic Number
The number of protons present in the nucleus of an atom is called atomic number or proton number. It is denoted by z. The proton in the nucleus of an atom is equal to number of electrons revolving around its nucleus.
Mass Number
The total number of the protons and neutrons present in the nucleus of an atom is called mass number. The protons and neutrons together are called nucleon. Hence it is also known as nucleon number. It is denoted by A. the number of neutrons present in the nucleus of an atom is rperesented by N.
Mass Number = No of Protons + No of neutrons
A = Z + N

Isotopes
The atoms of same elements which have same atomic number but different mas number are called Isotopes. The number of protons present in the nucleus of an atom remains the same but number of neutrons may differ.
Isotopes of Different Elements
Isotopes of Hydrogen
________________________________________
Hydrogen has three isotopes:
1. Ordinary Hydrogen or Protium, H.
2. Heavy Hydrogen or Deutrium, D.
3. Radioactive Hydrogen or Tritium, T.
Protium
Ordinary naturally occurring hydrogen contains the largest percentage of protium. It is denoted by symbol H. It has one proton in its nucleus and one electron revolve around the nucleus.
 Number of Protons = 1
 Number of Electrons = 1
 Number of Neutrons = 0
 Atomic Number = 1
 Mass Number = 1
Deutrium
Deutrium is called heavy hydrogen. The percentage of deutrium in naturally occuring hydrogen is about 0.0015%. It has one proton and one neutron in its nucleus. It has one electron revolving around its nucleus. It is denoted by symbol D.
 Number of Proton = 1
 Number of Electron = 1
 Number of Neutrons = 1
 Atomic Number = 1
 Mass Number = 2
Tritium
Radioactive hydrogen is called tritium. It is denoted by symbol T. The number of tritium isotope is one in ten millions. It has one proton and 2 neutrons in its nucleus. It has one electron revolving around its nucleus.
 Number of Proton = 1
 Number of Electron = 1
 Number of Neutron = 2
 Atomic Number = 1
 Mass Number = 3



Chapter : Periodicity of Elements and Periodic Table



Definitions
Periodic Table
A table of elements obtained by arranging them in order of their increasing atomic number in which elements having similar properties are placed in the same group is called Periodic Table.
Group
The vertical column of elements in the periodic table are called Groups.
Period
The horizontal rows of elements in the periodic table are called Periods.
Periodicity
The repetition of physical and chemical properties of elements periodically is called Periodicity of Properties.
Periodic Law
Physical and chemical properties of elements are periodic function of their atomic masses.
Metal
Elements which are good conductors of heat and electricity are malleable and ductile and have a metallic luster are called Metals like Sodium, Potassium, Gold, Copper etc.
Non-Metals
Elements which are non or bad conductor of heat and electricity are neither malleable or ductile and have no metallic luster are called Non-Metals like Carbon, Nitrogen, Chlorine etc.
Metalloids
Metalloids are semi metals have the properties which are intermediate between a metal and non-metal like Boron, Silicon, Germanium, Arsenic, Antimony etc.

Law of Triads
A German Chemist, Dobereiner (1829), arranged chemically similar elements in groups of three on the basis of their atomic masses called Triads and it was found that atomic mass of the middle element was approximately equal to the average of atomic masses of other two elements. This is known as Law of Triads.
Drawback or Defect
As very few elements could be arranged in such groups, this classification did not get wide acceptance.

Law of Octaves
An English Chemist Newland (1864) stated that if the elements were arranged in the ascending order of their atomic masses, every eight element will have similar properties to the first. This is knows as Law of Octaves.
Drawback or Defects
1. Noble gases were not discovered at that time and no place was reserved for the undiscovered noble gases.
2. In the same way no blank spaces for the undiscovered elements were present in his table.

Mendeleyv's Period Table and Periodic Law
Russian Chemist, Mendeleyv's (186) who wa working separately from Lother Mayer published a table of elements.
According to Mendeleyv's when the element were arranged in order of their increasing atomic mases, the elements with similar properties were repeated after regular interval and were placed one above the other.A table obtained in this manner is called Periodic Table. Mendeleyv's stated this periodicity in the form of Periodic Law.

Important Features of Mendeleyv's Periodic Table
________________________________________

The important features of Mendeleyv's Periodic table are:
Periods and Groups
The horizontal rows which run from left to right in Periodic Table are called Periods and they are twelve in number.
The vertical rows which run from top to bottom in periodic table are called groups and they are eight in number.
Vacant Spaces
Mendeleyv's left many vacant spaces for the still unknown elements. For example, next to Calcium (40) should be Titanium (48) but it resembled silicon (28) instead of Aluminium (27). He left vacant space for element with atomic mass 44.
Discovery of New Element
Mendeleyv's discovered new elements and also guessed their atomic mass and properties.
Atomic Mass Correction
Mendeleyv's corrected the atomic masses of certain elements on basis of their properties and provided proper place to them in the periodic table.

Defects in Mendeleyv's Periodic Table
________________________________________

The Mendeleyv's Period Table has following defects:
Irregular Position of Some Elements
According to Mendeleyv's Periodic Law Potassium (39) should be placed before Argon (40) but he placed Argon (40) before Potassium (39) which goes against his law.
Position of Isotopes
Mendeleyv's periodic table gives no indication about the position of isotopes.
Structure of Atom
Mendeleyv's Periodic table gives no idea about structure of atoms.
Position of Lanthanides and Actinides
Lanthanides and Actinides have not been given proper place in Periodic Table.
Coinage and Alkali Metals
Alkali metals and coinage metals with different properties are placed in the same group. This defect has been replaced by placing them into two sub groups.

Modern Periodic Law and Modern Periodic Table
Modern Periodic Law
Physical and chemical properties of the elements are periodic function of their atomic number. Mosely (1913) says that atomic mas is not fundamental property. Due to some defects present in Mendeleyv's periodic law, Mosely introduced the concept of anomic number for the elements.
Example
When isotopes were discovered, it was thought advisable to arrange the elements on basis of their atomic number instead o increasing atomic mases. Isotopes were needed different position in the Mendeleyv's periodic table. Hence Mendeleyv's periodic law was modified.

Modern Periodic Table
When Mendeleyv's periodic law was modified and new elements were discovered. This forcd the scientists to change Mendeleyv's periodic law.
The electronic configuration of atoms also played an important role in he arrangement of the modern periodic law. This form of periodic table is called "Long form of Periodic Table" because it contains eighteen groups instead of eight but seven periods instead of twelve.

Group I - The Alkali Metals
The elements of group I are called "Alkali Metals". The word alkali is derived from an Arabic word meaning Ashes.
Elements of Group I
 Lithium
 Sodium
 Potassium
 Rubidium
 Cesium
 Francium
Properties of Group I
1. They are mono atomic.
2. They exist in solid metallic state.
3. Outer most shell of these elements is incomplete having one electron.
4. Elements of this group are highly reactive.
5. Elements of this group have large tendency to form compounds.
6. Elements of this group are strongly electro-positive.

Group II - The Alkaline Earth Metals
The elements of group II are called Alkaline Earth Metals. These elements occur in nature as silicate mineral and their oxides and hydroxides are strongly basic. Therefore these elements are called Alkaline Earth Metals.
Elements of Group II
 Beryllium
 Magnesium
 Calcium
 Strontium
 Barium
 Radium
Properties of Group II
1. They are mono atomic.
2. They exist in solid state.
3. Outer most shell of these elements is incomplete having two electrons.
4. Elements of this group are moderately reactive.
5. Elements of this group have moderate tendency to form compounds.

Group III - The Boron or Aluminium Family
The elements of group III exist in solid state.
Elements of Group III
 Boron Metalloid
 Aluminium Metal
 Gallium Metal
 Indium Metal
 Thallium Metal
Properties of Group III
1. They are mono atomic.
2. They exist in solid state.
3. Outer most shell of these elements is incomplete having three electrons.
4. Elements of this group are quite reactive.
5. Elements of this group have moderate tendency to form compounds.

Group IV - The Carbon and Silicon Family
Elements of Group IV
 Carbon
 Silicon
 Germanium
 Tin
 Lead
Properties of Group IV
1. They are mono atomic.
2. They exist in solid state.
3. Outermost shell of these elements is incomplete.
4. Elements of this group are quite reactive.
5. Elements of this group have moderate tendency to form compounds.

Group V - The Nitrogen Family
Elements of Group V
 Nitrogen
 Phosphorus
 Arsenic
 Antimony
 Bismuth
Properties of Group V
1. Some are mono atomic and some are di-atomic.
2. Some of them exist in gaseous and some are in solid state.
3. Outermost shell of these elements is incomplete having five electrons.
4. elements of this group are quite reactive.
5. Elements of this group have quite tendency to form compound.

Group VI - The Oxygen Family
Elements of Group VI
 Oxygen
 Sulphur
 Selenium
 Tellurium
 Polonium
Properties of Group VI
1. Some are mono atomic and some are di-atomic.
2. Some of them exist in gaseous and some are in solid state.
3. Elements of this group have quite tendency to form compounds.
4. The tendency of forming covalent bond decreases from oxygen to polonium.
5. There is a gradual decrease in the ionization potential down the group.

Group VII - The Halogen Family
Elements of Group VII
 Fluorine Gas
 Chlorine Gas
 Bromine Liquid
 Iodine Solid
 Astatine Radioactive
Properties of Group VII
1. They are diatomic except At.
2. Halogens are very active non-metals.
3. Outer most shell of these elements is incomplete having seven electrons.
4. Elements of this group are highly reactive.
5. There is a gradual decrease in the ionization potential down the group.

Transition Elements
Definition
Elements in Group IB, IIB, through VIIB are known as Transition Elements because they show their properties which are transitional between higly reactive and strong electro-positive elements of S-block which form ionic compounds and p-block elements which form largely covalent compounds.
Properties of Transition Elements
1. Transition Elements have incomplete inner electron shells.
2. They show variable valency.
3. They show similar behaviour.
4. They all are metals.
5. They have strong inner atomic bonds.

Group 0, The Noble Gases
The elements of Group VIII A are called "Noble Gases" or "Inert Gases" or "Zero Group Elements".
Elements of Group 0
 Helium
 Neon
 Argon
 Krypton
 Xenon
 Radon
Properties of Group 0
1. They are mono atomic.
2. They exist in gaseous state.
3. Outer most shell of these elements is either complete or contains eight electrons.
4. These elements are mostly chemically non-reactive.
5. These elements have no tendency to form compounds (only a few of these compounds are known).

Atomic Radius
Definition
One half of the distance between the nucleus of two identical atoms when these are in close contact with each other is called Atomic Radius.
Unit
It is measured in angstrom unit A.
Trend in Period
The atomic radii decreases from left to right within a period in the periodic table. This is because nuclear charge increases with the increase of atomic number. But the number of shells remains same within a period.
Trend in Group
Atomic radius increases from top to bottom in a group. This is because, although nuclear charge increases from top to bottom but at the same time on new shell is also added for each successive element down the group.

Ionization Energy (I.E) or Ionization Potential (I.P)
Definition
The minimum energy needed to remove an electron from an isolated, gaseous atom in its ground state is called Ionization Energy.
Unit
It is expressed in electron volts or kilo-joules permole.
1 ev = 96.49kj
Factors Affecting Ionization Energy
The ionization energy of elements depends upon the following factors:
1. Effect of Nuclear Charge on I.E
The greater the nuclear charge the higher is the ionization energy.
2. Effect of Atomic Size
The larger the size of atom the lower is the ionization energy.
Trend of I.E in Period
Ionization energy increases from left to right in a period due to increase in nuclear change and decrease in atomic size.
Trend of I.E in Group
I.E decreases from top to bottom in a group due to increase in atomic size.

Electronegativity
Definition
The tendency of each atom in a covalent molecule to attract a shared pair of electrons towards itself is known as its electronegativity.
Factors Affecting Electronegativity
Electronegativity depends upon the following factors:
 Atomic size
 Atomic Number
 Electron Affinity
 Ionization Energy
Trend or Variation in the Period
Electronegativity increases from left to right within a period due to increase in nuclear charge and decrease in atomic size.
Trend or Variation in the Group
Electronegativity values decreases from top to bottom within a group due to increase in atomic size.

Electron Affinity
Definition
The energy change that occurs when an electron is gained by an atom in the gaseous state is known as Electron Affinity.
Electron Affinity for the addition of first electron is negative i.e. energy is released but for further addition of electrons it is positive because energy has to be added to over come repulsion between negative ion and electron.
Unit
It is measured in KJ/mol or in e.v per atom.
Factors Affecting Electron Affinity
 Atomic Size
 Nuclear Charge
Tend or Variation of Electron Affinity in Group
Down the group in the periodic table, electron affinity decreases because the addition of a new shell to each atom decreases its force of attraction.
Trend or Variation of Electron Affinity in Period
In a period, the electron affinity increases from left to right because the incoming successive atoms have higher nuclear charge and attract electron more towards itself.



Chapter : STATE OF MATTER


States of Matter
Matter has three states:
1. Gas
2. Liquid
3. solid
These are physical states of matter. The three states of one matter may have different physical properties while their chemical properties are same. Water exists in three physical states solid (ice), liquid and gas(steam) has same chemical properties.

Kinetic Theory of Matter
The Kinetic theory was presented to explain the properties of gases and is called kinetic theory of gases. But this theory was also able to explain the composition of liquid and solid state of matter. So its is called Kinetic Theory of Matter.
According to Kinetic Theory of matter:
1. All matter is composed of atoms, molecules or ions.
2. These particles have kinetic energy due to which they are in the state of motion.
3. In gaseous state, these particles move in a straight line. They collide with one another and with the walls of container. In liquids the rate of their movement is very small but in solids, there is to and fro motion only.
4. Generally material particles can have three types of movements, i.e. translational, rotational and vibrational.

Solids
The state of matter which has definite shape and volume is called solid.
Properties of Solids
1. Definite Volume and Shape
The cohesive forces in solid substances are so strong that they keep their particles arranged in fixed positions. So due to restrict movements of particles, the solids have definite volume and shape.
2.Motion of Particles
The solid particles have vibrational motion only because these particles are held in fixed position by strong cohesive forces.
3. Effect of Heat
The physical state of solid substance can be changed by heating. On heating solid is converted to liquid and gaseous state. Heat increases the kinetic energy of the particles and they start vibrating at higher frequency. At a particular temperature the vibrational motions become fast that they overcome the cohesive forces and solid melts to liquid.
4. Melting Point
The temperature at which the solid is converted to liquid on heating is called melting point. At melting point, the particles of solid loose their means position and their arrangement. The solid collapses and turns to liquid.
5. Sublimation
The conversion of some solids directly into gaseous state on heating is called sublimation. Iodine, ammonium chloride and naphthalene change directly into vapour state upon heating.

Liquid
The state of matter having definite volume but indefinite shape is called liquid.
Properties of Liquid
1. Volume
Liquids have definite volume. In liquid particles are very close to one another and have cohesive forces among the particles. Due to the presence of cohesive forces, liquids have definite volume and keep their level as well.
2. Shape
Liquids do not have any specific shape. They adopt the shape of the container. The molecules of liquid are able to move. Due to this random motion the molecules of liquid do not have fixed position and as a result, a liquid does not have any specific shape.
3. Evaporation
Conversion of liquid into its vapours at any temperature is called evaporation. The molecules of liquid come to the surface of liquid and escape by overcoming cohesive forces. So liquid is converted to vapours at all temperature.
4. Boiling Point
The temperature of a liquid at which its vapour pressure becomes equal to the atmospheric pressure is called boiling point.

Gas
The state of matter which does not have definite shape and volume is called gaseous state.
Properties of Gaseous State
1. Indefinite Volume and Shape
In gaseous state, the molecules have insignificant cohesive forces among themselves. They move very fast in all possible directions. As a result, a gas neither has fixed shape nor a fixed volume.
2. Kinetic Energy of the Particle of a Gas
Gas particles have very high kinetic energy as compared to liquid and solid state.
3. Pressure
The molecules of a gas are in the state of random motion. The molecules of gas not only collide with one another but also with the walls of the container in which they are enclosed. Due to their collision, the velocity of the molecules changes every moment. The pressure exerted by gas is also due to the collision of its molecules with the walls of the container.
4. Elastic Collision
The collision of gas molecules is elastic in nature which means that the total energy of the colliding molecules remains the same before and after the collision.
5. Kinetic Energy
The kinetic energy of molecules of gas is very high as compared with solid and liquid.

Diffusion
The movement of molecules from a higher concentration to a lower concentration is known as Diffusion.
If the concentration of molecules at a particular place is higher, they start moving towards a place where their concentration is lower. When the concentration of molecules at both the places becomes equal the process of diffusion stops.
Diffusion in Gases
The molecules of one gas can diffuse easily into the molecules of other gas. For example if an open bottle of a perfume is kept in a room, its smell will spread uniformly throughout the room. The liquid perfume present in the bottle volatilized slowly and its vapours diffuse through out the room.
Graham's Law of Diffusion
Scottish Chemist, Thomas Graham (1833) discovered that lighter gs can diffuse through porous pot faster than the heavier one. This is called Graham's Law of Diffusion.
Hydrogen being lighter gas will diffuse faster than oxygen or carbon dioxide.
Diffusion in Liquids
Liquid molecules can also diffuse because they have free movement. Since the molecules of liquid move comparatively slowly than gas molecule, their rate of diffusion are also lesser than gases.

Brownian Movement
Robert Brown (1927) discovered this phenomenon:
The free movement of the molecules of gases and liquid is called Brownian Movement."
When a pollen grain is put in water. The movement of pollen grain in water is observed by microscope. It is observed that pollen grain is continuously moving in all directions. This free movement of pollen grain was due to the free movement of water molecules. The colliding water molecules will also force pollen grain to move as well. The students can observe Brownian movement with the help of simple experiment.
Experiment
Put a drop of milk on a microscope slide and cover it with cover slip. Put it under microscope and observe it. You will see small particle of fat moving randomly in milk. The movement of fat particles is actually due to the movement of water molecules in milk.



Chapter : SOLUTION OF SUSPENSION


Solution
A homogeneous mixture of different chemical substances which has uniform chemical composition through out and shows uniform physical properties is called solution. For example dissolve a small amount of copper sulphate in water the water will become blue. If this blue liquid is filtered, it will pass through the filter paper without leaving any solid. The mixture thus prepared is called a solution.

Binary Solution
A solution which is formed by mixing two substances is called binary solution. For example solution of glucose and water.

Solute
The component of a binary solution which is in lesser amount is called solute. For example in copper sulphate solution, copper sulphate is solute.

Solvent
The component of a binary solution which is in greater amount is called solvent. For example in copper sulphate solution, water is solvent.

Saturated solution
A solution in which maximum amount of a solute has been dissolved at a particular temperature and in which the dissolved form of solute is at equilibrium with its undissolved form is called saturated solution.

Unsaturated Solution
Solution which can dissolve further amount of a solute at a [particular temperature is called an unsaturated solution.

Supersaturated Solution
The solution which contains even more amount of solute required to prepare saturated solution is called super saturated solution. The hot saturated solution of compound like sodium thiosulphate does not crystallize its solute if cooled slowly without disturbance. Such a solution is called supersaturated solution.

Dilute Solution
A solution which contains small amount of a solute as compared to the solvent is called dilute solution.

Concentrated Solution
A solution which contains excess amount of a solute as compared to that of a solvent is called a concentrated solution.

Concentrated Solution
The amount of solute present in given quantity of solvent is called concentration of solution. The concentration of a solution can be expressed in many ways depending upon the amount o solute and solvent present in it.

Concentration of Solution
The amount of solute present in given quantity of solvent is called concentration of solution. The concentration of a solution can be expressed in many ways depending upon the amount of solute and solvent present in it.
Percentage by Mass
The percentage of solute by mass is the mass of solute present in hundred part of the solution. For example 5% hydrogen peroxide solution by mass means that 5g hydrogen peroxide are dissolved in 95g of water to give 100g of solution.
Percentage of Mass = (Mass of Solute/Mass of Solution) x 100
Percentage by Volume
The concentration unit expresses the volume of solute present in 100cm3 of solution. For example 15% solution of alcohol by volume will mean that 15cm3 alcohols are present in 100cm3 of solution. (Here 3 represents cube)
Percentage by Volume = (Volume of Solute/Volume of Solution) x 100
Molar Solution
The solution that contains one mole of solute in 1dm3 of solution is called a molar solution. The concentration of this solution is expressed as M.
Molarity
Molarity of a solution is the number of moles of solute present in 1dm3 of the solution. It is expressed as M.
M = Number of Moles of Solute/Volume of Solution in dm3
or
M = (Mass of solute/Molecular Mass) x (1/ Volume of Solution in dm3)

Crystallization
The process in which crystal separates from saturated solution on cooling is called crystallization. It is a useful process because it can be used to purify the impure solid compounds. It can also be used to separate a mixture of solids.

Hydration
The ions surrounded by solvent molecules in solution are called solvated ions. If water is a solvent these ions are called hydrated ions.

Suspension
A suspension in such a mixture in which solute particles do not dissolved in solvent and if filtrated its particles do not pass through the pores of filter paper.

Colloidal Solution
In a colloidal solution the solute particles are slightly bigger than those present in a true solution but not big enough to seen with naked eye.

Standard Solution
A solution whose molarity (strength) is known is called Standard Solution.

True Solution
A True Solution is such a mixture in which solute particles are completely homogenized in the solvent for example solution of sodium chloride or copper sulphate in water.

olubility
Solubility o a solute in a particular solvent is defined as the amount of solute in grams, which can dissolve in 100g of the solvent at a particular temperature to give a saturated solution.
or
The amount of a solute in gram moles, which can dissolve in one kilogram of the solvent at a particular temperature, to give a saturated solution.
Factors Affecting the Solubility
________________________________________
Effect of Solvent
Similar solvents dissolve similar solutes, i.e. if the chemical structure and the electrical properties such as dipole moment of solute and solvent are similar, the solubility will increase. If there is dissimilarity in properties, then either the solute will not dissolve or there will be very little solubility.
Effect of Solute
Different solutes have different solubility's in a particular solvent e.g. if the saturated solutions of table sugar and sodium chloride are prepared, it is found that the concentration of sodium chloride solution is 5.3 molar while that of sugar solution is 3.8 molar. In other words, the solubility of sodium chloride in water is far greater than that of sugar. This is due to the fact that the attraction of sodium (Na+ and chloride (Cl-) ions with water is greater than that of sugar molecules with water.
Effect of Temperature
Change in temperature has different effects on the solubility of different compounds. Usually the solubility increase with the increase in temperature but it cannot be taken as a general rule. The solubility of compounds like lithium carbonate, calcium chromate decreases with the increase in temperature. The solubility of gases in water also decreases with the increase in temperature. On the other hand, there are a large number of compounds whose solubility in water increase with the increase in temperature e.g. sodium nitrate, silver nitrate, Potassium chloride etc. the solubility of sodium chloride in water does not increase appreciably with the increase in temperature.



Chapter : ELECTRO CHEMISTRY


Electro-Chemistry
The branch of chemistry which deals with the study of chemical energy to electrical energy or electrical energy to chemical energy is called electro-chemistry.

Conductors
Those substances through which electric current can pass are called conductors. For example all metals are conductors.

Non-Conductors
Those substances through which electric current cannot pass are called non-conductors. For example plastic, wood are non-conductors.

Electrolysis
The process in which electricity passes through the aqueous or infused state of some substance. The substances itself decompose into its component. This process is called electrolysis.

Electrolyte
The compound in molten state or in aqueous solution through which electricity can pass are called electrolyte.

Non-Electrolyte
Those compounds through which electricity cannot pass are called non-electrolyte.

Strong Electrolyte
The substances which are highly soluble and completely ionized are called strong electrolyte. For example acids, bases and salts are strong electrolytes.

Weak Electrolyte
The substances which are not highly soluble and remain in un-ionized form are called weak electrolyte.

Electroplating
A process in which metal is deposited on the surface of another metal by electrolysis is called electroplating.

Objectives of Electroplating
________________________________________
Decoration
It is done for decoration. Noble and precious metals like gold or silver are deposited on the inferior metals to enhance their beauty and look beautiful.
Protection
Electroplating is done to protect the metals from rusting as well as from attack of other substance like organic acids and acidic gases.
Repair
It can be used to repair the broken machinery by electroplating with other metals. Usually the metals like copper, silver, chromium, nickel and gold are used for electroplating.

Procedure of Electroplating
________________________________________
The metal which is to be electroplated is first cleaned with sand and then washed with caustic soda solution and finally with a lot of water.
This metal is made cathode and the metal which is going to be deposited is made anode. The electrolyte is a salt of metal being deposited and electroplating is carried out in a tank made of cement, glass or wood. It is called an electrolytic tank.
The electrolyte should have following properties:
1. It must be very soluble in water.
2. It must be good conductor.
3. Cheap
4. May not easily oxidized or reduced or hydrolyzed.
(Diagram)




DIFFERENCES


Metals and Non Metals
Metals
1. Metals have luster shine surface.
2. Metals reflect heat and light.
3. Metals conduct heat and electricity
4. Metals are ductile and can be drawn into wire.
Non-Metals
1. Non-Metals have no luster.
2. Non-Metals usually don't reflect heat and light.
3. Non-Metals do not conduct heat and electricity.
4. Non-Metals are non ductile and cannot be drawn into wire.
5. Non-Metals are non-malleable and can not form sheets.

Homogeneous and Heterogeneous Mixture
Homogeneous Mixture
1. Those mixtures, which have uniform composition throughout their mass are called homogeneous mixtures.
2. Homogeneous mixture has only one phase through out its mass.
3. Homogeneous mixture are also known as solution.
4. Examples: Salt and water, Sugar and water.
Heterogeneous Mixture
1. Those mixtures, which do not have uniform composition through their mass are called Heterogeneous Mixture.
2. Heterogeneous Mixture has more than one phase through out its mass.
3. Heterogeneous Mixture are not solutions.
4. Examples: Rocks, Soil, Food products.

Molecular and Empirical Formula
Molecular Formula
1. Formula which shows the actual number of atoms of each element present in a molecule is called Molecular Formula.
2. Molecular Formula shows the structure of compound.
3. Two or more compounds cannot have same Molecular Formula.
4. Molecular Formula = n x Empirical Formula.
5. It represents covalent compounds only.
Empirical Formula
1. formula, which shows the relative ratio of atoms of each element present in a molecule, is called Empirical Formula.
2. Empirical Formula can not show the structure of compound.
3. Two or more compounds can have same Empirical Formula.
4. Empirical Formula = Molecular Formula / n
5. It represent an ionic compound as well as a covalent compound.

Symbol and Formula
Symbol
1. A symbol is an abbreviation for the chemical name of an element and represents only one atom of the element.
2. It represents one atom of an element.
3. Symbol is written for elements.
4. Examples: Na, Br, Cl, F etc.
Formula
1. Representation of compound in terms of symbols is called formula. It represents one atom of an element.
2. It represents atoms of same or different elements present in one molecule.
3. It represents an ionic compounds as well as a covalent compound.
4. Examples: H2O, NH3 etc.

Gram and Gram Molecule
Gram
The atomic mass of an element expressed in grams is called gram atomic mass.
2. It is associated with element only.
3. It is the mass of one atomic mole.
4. One gram atom of any substance contains 6.02 x 10(23) atoms. (23 is the power of 10).
Gram Molecule
1. Molecular mass of any element or compound expressed in grams is called gram molecule.
2. It is associated with element and compound.
3. It is the mass of one molecular mole.
4. One gram molecule of any substance contains 6.02 x 10(23) atoms. (23 is the power of 10).

Atom and Molecule
Atom
1. It is the smallest particle of an element which can enter into a chemical reaction.
2. It is represented by a symbol of the element.
3. It shows the properties of the element.
4. It retains its identity in a chemical reaction.
Molecule
1. It is the smallest particle of a substance which can exist and show all the properties of the substance.
2. It is represented by a molecular formula of the substance.
3. It shows the properties of the substance.
4. It does not retain its identity in a chemical reaction.

Exothermic and Endothermic Reactions
Exothermic Reaction
1. Those chemical reactions in which heat energy is evolved are called exothermic reactions.
2. In exothermic reactions the enthalpy of products is lower than the reactants. H is therefore negative for an exothermic reaction.
3. During endothermic reaction, the system becomes colder and net potential energy of substance increases.
4. The energy is absorbed during these reactions.
5. The temperature of reaction therefore decreases.
Endothermic Reactions
1. Those chemical reactions in which heat energy is absorbed are called endothermic reactions.
2. In endothermic reactions the enthalpy of reactants is lower than the products. H is therefore positive in endothermic reaction.
3. During endothermic reaction, the system becomes colder and net potential energy of substance increases.
4. The energy is absorbed during these reactions.
5. The temperature of reaction therefore decreases.

Physical and Chemical Properties
Physical Properties
1. The physical properties of a substance are those characteristics which serve to distinguish it from other substance but do not deal with its ability to undergo chemical changes.
2. These are related to the physical state of matter.
3. Examples: Formation of ice from water, formation of a magnet from ice etc.
Chemical Properties
1. The chemical properties of a substance indicate the ability of a substance to undergo chemical changes.
2. They are related to the chemical change of a substance.
3. Examples: burning of paper, rusting of iron.

Electrolyte and Non-Electrolyte
Electrolytes
1. Electrolytes conduct electricity in molten or in solution form.
2. These form positive and negative ions when dissolved in water e.g. NaCl form Na+ and Cl- ions when dissolved in water.
3. Chemical changes occur when electric current is passed through the electrolyte.
4. Generally these are ionic or polar covalent compounds.
Non-Electrolytes
1. Non-electrolytes do not conduct electric current in molten or in solution form.
2. These do not form positive and negative ions when dissolved in water e.g. Urea, sugar, glucose etc.
2. No chemical change occurs in them on passing current.
3. Generally these are non polar covalent compounds.
4. Generally these are non polar covalent compounds.

Acid and Base
Acid
1. Those compounds which provide hydrogen ion (H+) in aqueous solutions are called Acids.
2. An acid is a substance which produces H+ ions in aqueous solution.
3. Acid is a species (a compound or ion) which donates or tends to donate a proton (H+).
4. An acid is a species (molecule or ion) which can accept a pair of electron. An acid is also called an electrophile (electron loving).
5. They have sour taste.
6. Acid turn blue litmus red methyl orange red.
Base
1. Those compounds, which provides hydroxyl (OH-) ion in aqueous solution, are called bases.
2. A base is a substance, which gives (OH-) in aqueous solution.
3. A base is a species, which accepts or tends to accept a proton.
4. A base is a species (molecule or ion) which can donate a pair of electrons. A base is also called a nucleophile (Nucleus loving).
5. Bases have bitter taste.
6. Bases turn red litmus to blue, colorless phenolphthalein to pink and methyl orange to yellow.

Ionic and Covalent Bond
Ionic Bond
1. Ionic bond is formed by complete transfer of electrons from one atom to another atom.
2. Ionic bond is always formed between different atoms. E.g. NaCl, CaCl2.
3. In ionic bond atoms have very large electro-negativity and ionization energy difference.
4. This bond is usually formed between metals and non-metals.
5. This bond is very strong.
6. As a result of this bond ionic compounds are formed.
7. It is always formed between two different atoms.
8. It is formed when difference of electro-negativity of combining atoms is 1.7 or more.
Covalent Bond
1. Covalent bond is formed by the mutual sharing of electrons between two atoms.
2. Covalent bond may be formed between similar or dissimilar atoms e.g. H2, O2, HCl etc.
3. In covalent bond atoms have very small electro-negativity or ionization energy difference.
4. This bond is usually formed between non-metals only.
5. This bond is comparatively less strong.
6. As a result of this bond covalent compounds are formed.
7. It is formed between similar and different types of atoms.
8. It is formed when difference of electro-negativity of combining atoms is less than 1.7.

Ionic and Covalent Compounds
Ionic Compounds
1. The ionic compounds are usually solid, hard and brittle.
2. The ionic compounds are good conductors of electricity either in fused state or in the form of aqueous solution.
3. Ionic Compounds have high melting points and boiling points.
4. Ionic compounds have high melting points and boiling points.
5. Covalent compounds are mostly volatile.
Covalent Compounds
1. Covalent compounds exist in all the three states i.e. gas, liquid and solid.
2. A pure covalent compound does not conduct electricity.
3. These have usually low melting and boiling points.
4. These are soluble in water.
5. These are insoluble in water but soluble in organic solvents.

Co-Ordinate Covalent and Covalent Bond
Co-Ordinate Covalent Bond
1. It is a bond in which the shared electron pair is denoted by one atom only.
2. One atom donates electrons but other has no contribution.
3. Lewis acids and bases always from this bond.
4. It is represented by ->.
5. It is formed by the donation of an electron apir by one of the two bonded atoms.
6. It is formed by the completely filled atomic orbital.
Covalent Bond
1. It is a bond formed by the mutual sharing of electrons.
2. In the shared electron pair both atoms have equal contribution.
3. Lewis acids and bases do not form this bond.
4. It is represented by _.
5. It is formed by the mutual sharing of electrons between atoms.
6. It is formed by the overlap of partially filled atomic orbital.

Polar and Non-Polar Covalent Bond
Polar Covalent Bond
1. The covalent bond between two atoms having different electro-negativity is called a polar covalent bond.
2. In a polar bond, the shared electron pair is not equally attracted by the bonded atoms.
3. Bonded atoms become slightly charged and acquire partial =ve and -ve charges.
4. It has an ionic character.
5. The bond energy is greater.
Non-Polar Covalent Bond
1. The covalent bond between two atoms having same electro-negativity is called a non-polar covalent bond.
2. In a non polar bond, the shared electron pair is equally attracted by the bonded atoms.
3. Bonded atoms remain electrically neutral and do not acquire partial charges.
4. It has no ionic character.
5. The bond energy is lesser.

Electrolytic and Galvanic or Voltaic Cell
Electrolytic Cell
1. It is a device for converting electrical energy into chemical energy. It means by passing current through an electrolyte, chemical reaction takes place.
2. It consists of a vessel containing an electrodes and a source of direct current (battery).
3. Example: Electrolysis of aqueous solution of NaCl.
Galvanic or Voltaic Cell
1. It is a device for converting chemical energy into electrical energy. It means spontaneous redox reaction is used for the production of electric current. This cell was prepared by L.Galvani and A.Volts, hence named as Galvanic or Voltaic Cell.
2. It consists of two half-cells. Each half cell consists of an electrodes and the solution with which it is in contact.
3. Example: Daniel Cell-Zn/ZnSO4 and Cu/CuSO4 cell.

Solution and Suspension
Solution
The size of particles is between 0.1 to 1nm.
2. Particles cannot be seen with low power microscope.
3. It is homogeneous.
4. Particles do not settle down.
5. It is transparent.
6. Components cannot be separated by filtration.
Suspension
1. The size of particles is larger than 1000nm.
2. Particles can be seen by low power microscope.
3. It is heterogeneous.
4. Particles settle down.
5. It is not transparent.
6. Components can be separated by filtration.



GLOSSARY



Acidity
The acidity of a base is defined as the number of ionizable hydroxyl groups in its molecule.
Anode
It is an electrode through which electrons enter the external circuit.
Alpha Rays
There are positively charged particles emitted from a radioactive substance. They carry two positive charges and are called helium nuclie.
Analytical Chemistry
It is the branch of chemistry which discusses the analytical methods forgetting information about chemical compounds and chemical processes.
Atomic Number
Number of positively charged particles (protons) present in the nucleus of an atom.
Atomic Size
Average distance between the nucleus of an atom and its outermost electronic shell. Its units are nm or pm.
Arrehenius Acid
It is a chemical compound which gives proton (H+) in water.
Arrehenius Base
It is a chemical compound which gives hydroxide ion (OH-) in water.
Atomic Spectrum
Spectrum of radiations emitted by the excited atoms when they come to the normal state.
Acidic Salts
An acidic salt is obtained when hydrogen atoms present in an acid, are partially replaced by metallic atoms.
Alchemist
A scientist trying to convert cheaper metals into precious metals is called Alchemist and this branch of chemistry is called Alchemy.
Atomic Mass
The mass of an element relative to the unit mass, which is 1/12th o the mass of C-12.
Ampere
The amount of electric current which liberate one electrochemical equivalent of a substance per second during electrolysis of that substance is called ampere.
Biochemistry
It is the study of chemical compounds present in living things.
Balancing of Chemical Equations
Equating the atoms of reactants with those of products.
Beta Rays
These are electrons emitted from a radioactive substance.
Brownian Movement
The free movement of the molecules of gases and liquids is called Brownian movement.
Bronsted Acid
A compound which can donate proton.
Bronsted Base
A compound which can accept proton.
Basicity
The basicity of an acid is defined as the number, of ionizable hydrogen atoms present in its molecule.
Basic Salts
A basic salt is obtained when the hydroxyl groups present in a base are partially replaced by some other groups.
Boiling Point
A temperature at which a liquid changes into gaseous state.
Chemistry
The branch of science, which deals with the composition of matter changes in matter and the laws or principles which govern these changes.
Chemical Equation
The representation of a chemical change in terms of symbols and formulas.
Covalent Solid
A solid in which there exist a covalent bond between atoms.
Covalent Bond
It is the force of attraction that arises between two atoms due to mutual sharing of an electron pair.
Co-Ordinate Covalent Bond
When the shared pair of electrons is provided by one of the bonded atoms, a coordinate covalent bond is formed.
Cohesive Forces
The forces of attraction present between the particles of solid, liquid and a gas.
Cathode Rays
Rays emitted from cathode in the discharge tube.
Colloidal Solution
A solution in which solute particles are bigger than those present in a true solution and which cannot be filtered.
Conductor
A substance which allows electric current to pass through it.
Cathode
It is an electrode through which electrons leave the external circuit.
Concentration of a Solution
The amount of a solute which has been dissolved in a particular amount of a solvent.
Concentrated Solution
A solution, which contains an excess amount of a solute as compared to that of a solvent.

Cell
The vessel containing reacting substances in which transfer of electrons takes place is called cell.
Coulomb
It is unit of electric current. When one ampere electric current is passed for one second the quantity of electric current is one coulomb.
Discharge Tube
A glass tube containing a gas at a very low pressure and provided with electrodes to study the passage of electricity through the gas.
Dipole-Dipole Forces
The forces of attraction which originate due to the difference in electro negativities of the bonded atoms in polar molecules.
Diffusion
The movement of molecules from a higher concentration to a Lowr concentration is called Diffusion.
Dilute Solution
A solution, which contains a small amount of a solute as compared to that of a solvent.
Double Salts
When two typical salts are crystallized together a double salt is formed. The physical properties of the crystals of double salt are different from those of the component salts.
Doberiner's Law of Triads
Dobereiner arranged similar elements in sets of three, called Triads. Atomic mass of the middle atom of a triad was equal to the average of the atomic masses of first and third members.
Degree of Ionization
It is the extent to which an electrolyte ionizes in water.
Experiment
An experiment is an activity performed under suitable conditions with specially designed instruments to get the required information.
Empirical Formula
The formula of a compound which shows the minimum ratio present between the atoms.
Electron Affinity
The amount of energy given out when an electron is absorbed in the outermost electronic shell of all isolated gaseous atom. Its units are KJ/mol.
Electro-Negativity
It is the power of an atom to attract the shared pair of electrons.
Evaporation
The continuous escape of the molecules of a liquid from its surface.
Elastic Collision
When gas molecule collides with each other their total energy does not decrease or increase. This type of collision is called an elastic collision.
Electrolytic-Cell
In a non-spontaneous oxidation-reduction reaction takes place with the help of electrical energy.
Electro-Chemistry
It is that branch of chemistry in which chemical energy is converted into electrical energy or electrical energy is converted into chemical energy.
Electrolytes
When electricity is passed through an ionic compound which is either in the fused state or in the form of aqueous solution, it is decomposed into its constituents. The ionic compound is called an electrolyte.
Electrolysis
The passage of electricity through an electrolyte is called electrolysis.
Electrochemical Series
A list of ions in which they are arranged in the order of their ability to get discharged.
Electroplating
The process of depositing a metal on another metal with the help of electricity.
Exothermic Reaction
Those chemical reactions during which heat is evolved.
Endothermic Reactions
Those chemical reactions in which heat energy is absorbed.
Enthalpy of Reaction
Heat of reaction which takes place at constant pressure.
Formula Mass
Formula mass is the mass of compound relative to the unit mass which is 1/12th of the mass of C-12.
Farad
It is the unit of charge 1 farad = 96500 coulomb.
Fusion
When a solid change into liquid this phenomena is called Fusion.
Heat of Neutralization
The heat given out during a neutralization reaction is called heat of neutralization.
Heat of Reaction
Heat evolved or absorbed during a chemical reaction which takes place at pressure.
Hypothesis
In the light of experiments, the scientists try to explain observations and facts. This tentative explanation is called hypothesis. It is quite possible that after sometime, on the basis of new experiments this hypothesis may be rejected.
Hydrogen Bonding
When a hydrogen atom is attached to any one of fluorine, oxygen and nitrogen atoms, there appears strong dipole forces which are called hydrogen bonding.
Hydrated Ions
Ions of a solute surrounded by water molecules are called hydrated ions.
Ionization
An electrolyte splits up into charged particles upon heating or in its aqueous solution. This process is called Ionization.
Ionic Theory
A theory which explains the process of electrolysis.
Intermolecular Forces
The forces of attraction present between the molecules of a compound.
Ionization Energy
The minimum amount of energy required to remove an electron from the outermost electronic shell of an isolated gaseous atom. Its unit is KJ/mol.
Ionic Bond
A bond formed due to the electrostatic force of attraction between oppositely charged ions.
Ionic Solid
A solid which is made up of ions of opposite charges.
Isotope
Atoms of an element having the same atomic number but different mass number.
Inorganic Chemistry
The study of all elements and their compounds except carbon is called inorganic chemistry.
Industrial Chemistry
The application of chemical knowledge in technology and industry and the preparation of industrial products are called industrial chemistry.
Inference
To deduce results after coordinating the observed facts with integrated scientific knowledge is called inference.
Kinetic Theory
The theory which explains the composition and properties of all the three states of matter.
Lewis Acid
A substance which can accept an electron pair.
Law
A theory when repeatedly gives the same results after experimentation and offers correct explanation of scientific facts it then becomes a law or principle.
Law of Conservation of Mass
Total mass of reactants is equal to that of products during a chemical reaction.
Law of Definite
A compound always contains elements combined together in a fixed ratio by mass.
Law Multiple Proportions
When two elements combine together to give more then one compounds, the different masses of an element, which combine with the fixed mass of the other element, have a simple ratio between them.
Law of Reciprocal Proportions
When two or more elements A and B combine separately with the fixed mass of the third element E the ratio in which they do so may be the same or some simple multiple of the ratio in which these two elements (A and B) combine with each other.
Molar Solution
A solution in which one mole of a solute has been dissolved in one dm3 of solution. It is represented as M.
Metallic Bond
When positively charged metal ions are held together by freely moving electrons, the bond formed is called a metallic bond.
Molecular Solid
A solid which has Vander Waal's forces present between its molecules.
Melting Point
A temperature at which a solid changes into a liquid.
Mass Number
The total number of protons and neutrons present in the nucleus of an atom.
Mendeleyv's Periodic Law
Properties of elements are a periodic function of their atomic masses.
Modern Periodic Law
Properties of elements are a periodic function of their atomic numbers.
Molecular Mass
Molecular mass is the mass of an element or a compound relative to the unit mass, which is 1/12th of the mass of C-12.
Molar Mass
The mass of an element or a compound which contains Avogadro's number particles.
Molecular Formula
The formula of an element or a compound which tells the actual number of atoms present in the molecule of that element or a compound.
Neutralization
Acids and bases react together to form salts and water and in this way they neutralize the properties of each other. This reaction is called Neutralization reaction.
Normal Salts
Salts, which neither have replaceable hydrogen atoms nor hydroxyl groups.
Non-Conductor
A substance through which electric current cannot pass.
Neutron
It is the smallest neutral particle present in the nucleus of atoms. Its mass is slightly more than that of a proton.
Nucleus
Central part of an atom where most of its mass is concentrated. Its size is very small as compared to the size of the atom.
Newland's Law of Octaves
If elements are arranged in the increasing order of their atomic masses every 8th element repeats the properties of the 1st element.
Oxidation
A chemical reaction in which oxygen is added or hydrogen is removed or electrons are lost.
Octet Rule
When an atom has eight electrons in its outer most shell, its is said to be stable and does not combine with other atom to reduce its energy. This is called octet rule.
Organic Chemistry
The branch of chemistry in which we study the compounds of carbon.
Observation
The process of observing natural phenomena with the help of five senses and the scientific equipment.
Orbits
The circular path of an electron around the nucleus.
pH Scale
The negative log of hydrogen ion (H+) concentration present in a solution is called pH. This scale measures the concentration of hydrogen ions present in a solution.
Percentage by Mass
Volume of a solute present in 100cm3 of a solution.
Percentage by Volume
Volume of a solute present in 100 cm3 of a solution.
Physical Chemistry
The branch of chemistry, which deals with the physical properties and physical behaviour of material things.
Prediction
The inference based on observed facts.
Proton
It is the smallest positively charged particle present in all kind of atoms. The mass of this particle is equal to the mass of the hydrogen nucleus (H+).
Positive Rays
Rays produced in the discharge tube, which are traveling in a direction opoposite to the cathode rays.
Reversible Reaction
Chemical reaction, which takes place both directions, forward as well as backward.
Reduction
A chemical reaction in which hydrogen is added or oxygen is removal or electrons are absorbed.
Radioactive Rays
Rays emitted from radioactive element or their compounds, which can cause fogging of the photographic plate.
Strong Acid
An acid which ionizes completely in water.
Strong Base
A base which can ionize completely in water giving excess of hydroxide ions.
Sublimation
Some solids, upon heating, change directly into vapors instead of changing into liquid.
Scientific Method
The method which helps to collect facts on the basis of observations and experiments. Theories and laws are then formulated to explain these facts.
Solute
The substance present in relatively lesser amount in a solution.
Solvent
the substance present in excessive amount in a solution.
Solvated Ions
Ions of a solute surrounded by solvent molecules in a solution are called solvated ion.
Saturated Solution
A solution, which contains the maximum amount of a solute at a particular temperature and which is unable to dissolve further amount of solute in it.
Supersaturated Solution
A solution which contains an amount of solute more than that required for the preparation of a saturated solution at a particular temperature.
Standard Solution
A solution whose concentration is known.
Solubility
The amount o solute in grams which can dissolve in 100 gm of solvent at a particular temperature to give a saturated solution.
Suspension
A mixture in which solute particles do not dissolve in solvent.
Strong Electrolytes
An electrolyte which completely ionize in water.
Transition Elements
Elements having incomplete penultimate (next inner to the outermost) electronic shell.
Theory
If a hypothesis is accepted (after discussion and experimentation) it is called a theory.
Thermo Chemistry
It is the branch of chemistry in which we study the heat changes during a chemical reaction.
Unsaturated Solution
A solution, which can dissolve further amount of a solute at a particular temperature, is called unsaturated solution.
Unified Atomic Mass Unit
Unit of a new scale, which is equal to 1/12th of the mass of C-12.
Voltaic Cell
In a cell a spontaneous oxidation-reduction reaction is used to produce electric current.
Weak Electrolyte
An electrolyte which undergoes partial ionization in water.
Weak Base
A base which ionizes partially in water.
Weak Acid
An acid which ionizes partially in water.
Water of Crystallization
The number of water molecules present in the crystals of a solid.



EXPERIMENT NO. 1


Viva Voce
Qs. 1. What is the chemical formula of common salt?
Ans. The chemical formula of common salt is NaCl.

Q.2. Which elements are present in common salt?
Ans. Common salt contains sodium and chlorine elements.

Q.3. What is the chemical name of Common salt?
Ans. The chemical name of Common salt is Sodium Chloride.

Q.4. What is the molecular weight of Sodium Chloride?
Ans. The molecular weight of Sodium Chloride is 58.5.

Q.5. What is the atomic weigth of Sodium?
Ans. The atomic weight of Sodium is 23.

Q.6. What is the atomic weigth of Chlorine?
Ans. The atomic weight of Sodium is 35.5.

Q.7. What do you understand by solute?
Ans. Anything which dissolves in a liquid is called Solute.
OR
Solution comprises of two constitiuents. That constituent which is less in quantity is called Solute.

Q.8. What is the name of that constituent which is present in smaller amount in the solution?
Ans. The constituent present in smaller point is called Solute.

Q.9. What is Solvent?
Ans. Any substance which can dissolve a substance to form a homogeneous mixture is called a solvent.
OR
The component of the solution present in greater amount is called Solvent.
EXAMPLE: When sodium chloride is dissolved in water then the water is known as Solvent.

Q.10. What do you understand by the term Solution?
Ans. A homogeneous mixture of two or more substances is called solution.
EXAMPLE: Homogeneous mixture of sugar and water is called solution.

Q.11. What is Solubility?
Ans. The Solubility of a substance can be defined as the amount of the substance that can be dissolved by 100 gms of the solvent at a particular temperature. Mathematically it can be expressed as
Solubility = Weight of solute in gm / Weight of Solvent in gm x 100

Q.12 What is Density?
Ans. Mass per unit volume of substance is called Density.

Q.13 What is the unit of density in M.K.S System?
Ans. gm/cm3 or gm/ml

Q.14. What is the unit of density in M.K.S System?
Ans. Kilogram/m3 or Kilogram/litre.

Q.15. What is the unit of density in British Engineering System?
Ans. Slug/(foot)3 or Slug per cubic foot.

Q.16. What is Mass?
Ans. The quantity of matter present in a substance is called its Mass.

Q.17. What is the unit of mass in C.G.S System?
Ans. Gram.

Q.18. What is the unit of mass in M.K.S. System?
Ans. Kilogram.

Q.19. What is the unit of mass in B.E.System?
Ans. Slug.

Q.20. What is Volume?
Ans. The space occupied by the substance is called its volume?

Q.21. What is the unit of volume in C.G.S system?
Ans. Cm3 or C.C.
Q.22. What is the unit of Volume in M.K.S System?
Ans. The unit of Volume in M.K.S System is (Metre)3 or Cubic Metre.

Q.23. What is the unit of Volume in B.E.System?
Ans. (Foot)3.

Q.24. What do you understand by Weight?
Ans. The force of attraction of the earth exerted on an object is called its weight.

Q.25. What is the unit of weight in M.K.S.System?
Ans. Newton.

Q.26. What is the unit of weight in C.G.S System?
Ans. Dyne.

Q.27. What is the unit of weight in B.E.System?
Ans. Pound.

Q.28. What is meant by Relative Density?
Ans. The ratio of the density of a substance to the density of water at 4oC is called its Relative Density.

Q.29. How will you express the formula of Relative Density mathematically?
Ans. Relative Density = Density of Substance / Density of water at 4oC

Q.30. What is the formula of Relative Density of Substance in terms of Mass of the Substance?
Ans. Relative Density = Mass of Substance / Mass of equal volume of water.

Q.31. What is the unit of Relative Density?
Ans. It has got no unit because it is a ratio.

Q.32. What is the density of water at 4oC?
Ans. The density of water at 4oC is 1 gm/cm3.

Q.33. Why do we consider the density of water at 4oC?
Ans. We consider the density of water at 4oC because it is maximum at this temperature.

Q.34. What is Specific Gravity?
Ans. Specific Gravity of a substance is the ratio of the density of a substance to the density of water at 4oC.

Q.35. What is the unit of Specific Gravity?
Ans. It has got no unit because it is a ratio.

Q.36. What is R.D.Bottle?
Ans. It is a small bottle of known Capacity having a glass stopper possessing fine hole used for finding the volume of liquid.

Q.37. What is the use of the density of a substance?
Ans. By the knowledge of the densities we identify different substances.

Q.38. How do you clean the R.D.Bottle?
Ans. R.D.Bottle is cleaned by Alcohal or Ether.

Q.39. Why is it advised to remove air bubbles from R.D.Bottle?
Ans. If the air bubbles are not removed then there will be loss in weight of Salt Solution.

Q.40. Which instrument is used for determining the mass of the substance?
Ans. Physical Balance is used for determining the mass of the substance?

Q.41. Which instrument is used for determining the weight?
Ans. Spring Balance is used for determining the weight of a substance.

Q.42. How do you find the Volume of Salt Solution?
Ans. As we talk Salt Solution in R.D.Bottle so its volume will be equal to the volume of the bottle mentioned on it.

Q.43. What is the difference between Mass and Weight?
Ans. MASS:
1. The quantity of matter present in a substance is called Mass.
2. Mass remains the same at all the places.
3. Mass is measured with a Physical Balance.
4. The unit of Mass in various systems of measurements is given below.
C.G.S. System _______ Gram
M.K.S. System _______ Kilogram
B.E. System _________ Slug
WEIGHT:
1. The force of attraction of the earth exerted on a substance is called its weight.
2. Weight changes as the distance from the centre of the earth changes.
3. Weight is determined with the help of Spring Balance.
4. The unit of weight in various systems of measurements is given below.
C.G.S. System _______ Dyne
M.K.S. System _______ Newton
B.E. System _________ Pound

Q.44. Does the weight of a substance remain the same at all the places or changes. Give the reason why does it happen?
Ans. The weight does not remain same at all the places. Weights depends upon the distance of substance from the centre of the earth.

Q.45. Which will occupy more space. 10 C.C of Cotton OR 10 C.C of Iron?
Ans. Both will occupy the same space.

Q.46. Which will have more mass. 20 C.C of Cotton OR 20 C.C of Iron?
Ans. 20 C.C of Iron will have more mass.

Q.47. Which will have more mass. 10 gm of Cotton OR 10 gm of Iron?

Ans. Both will have the same mass.

Q.48. Will the density of a substance be more or less on the mountain as compared to sea level?
Ans. There will be no change in the density.

Q.49. Which is heavier 20 gm of Iron or 20 gm of Cotton?
Ans. Both will have the same weight.

Q.50. Which will be denser 10 gm of Iron or 10 gm of Cotton?
Ans. Iron will be more denser. (In the question we are concerned with the density of the substance).
Q.51. Which kind of lever is the Physical Balance?
Ans. It is first kind of lever.

Q.52. What are the important parts of Physical Balance?
Ans. The important parts of Physical Balance are given below:
1. Beam
2. Adjusting Screws
3. Knife Edges
4. Stirrup
5. Pan
6. Vertical Pillar
7. Pointer
8. Scale
9. Plumb Line or (Spirtit Level)
10. Levelling Screws
11. Knobs

Q.53. What do you understand by the beam ofa Physical Balance?
Ans. The Beam is a horizontal frame work capable of turning freely with very little friction about an "Agate Knife Edge" at the centre called Fulcrum.

Q.54. How many Knife Edges are there in the Physical Balance?
Ans. There are three Knife Edges. One at the middle and two at the ends.

Q.55. What is the purpose of "Plumb Line"?
Ans. The purpose of the Plumb Line is to make the "Pillar" vertical and "Base" horizontal.

Q.56. Why is it advised that when "Balance" is not in use should not be raised too much?
Ans. The sharpness of the Knife Edge is preserved.

Q.57. What should be done if the Plumb Line is broken?
Ans. In such case the spirit level is used to test the level of the base of Physical Balance.

Q.58. Why do we place the "Physical Balance" in a glass case?
Ans. It is kept in glass case to prevent it from being disturbed by wind when weighing is going on and from being contaminated with Acid fumes and moisture.

Q.59. What are the conditions to be satisfied by a good balance?
Ans. A good balance must satisfy the following conditions. It must be
1. True
2. Sensitive
3. Stable

Q.60. On the Specific Gravity bottle, 25 ml, 50 ml and 20oC is written. What do you mean by that?
Ans. 25 ml and 50 ml means 25 Mililitre and 50 Mililitre which indicates the volume of the bottle. 20oC is the temperature at which the volume of that particular bottle is 25 ml or 50 ml.

Q.61. What is the Physical Balance?
Ans. It is the instrument for comparing the mass of an object with a known mass.

Q.62. What is the "Principle of Balance"
Ans. It works on the principle of First kind of Lever.

Q.63. On which pan do you place the weights?
Ans. The weights are placed on the right band.

Q,64. How will you find the density of the milk?
Ans. The density of the milk is determined by a special Hydrometer.

Q.65. What is the practical application of density?
Ans. It helps us to find whether the substance is pure or impure.

Q.66. What is the function of a Hydrometer?
Ans Hydrometer is used for finding the density of a liquid.

Q.67. What will be effect of density of a stone if it is broken into two pieces?
Ans. It will remain the same.

Q.68. Convert 865 milligrams into gram?
Ans. 965 m.gm = .865 gm

Q,69. Convert 75 milligram into gram?
Ans. 75 milligram = .075 gm.

Q.70. Convert 7 milligram into gram?
Ans. 7 milligram = .007 gram.

Q.71. How many C.C are there in one Litre?
Ans. 1000 C.C = One Litre.

Q.72. How many Milligrams are there in one gram?
Ans. 1000 mg = 1 gm.

Q.73. How many ml are there in one litre?
Ans. 1000 ml = 1 Litre.

Q.74. Why do we prefer Ether or Alcohal for rinsing the R.D.Bottle?
Ans. Ether and Alcohal evaporate quickly.

Q.75. Why does Kerosene Oil float on water?
Ans. Kerosene oil float on water because it is lighter than water.

Q.76. Why Kerosene Oil is lighter than water?
Ans. The Kerosene oil is lighter than water because its density is less than the density of water.

Q.77. Convert 5.24 gm into Milligram?
Ans. 5.24 gm = 5240 Milligram.



EXPERIMENT NO. 2


Vice Voce
Q.1. What is the formula of Sand
Ans. The formula of sand is SiO2.

Q.2. What are Magnetic Substances?
Ans. Those substance which are attracted by magnet are known as Magnetic Substance.

Q.3. What is a Magnet?
Ans. Any substance when suspended freely always points North and South and attracts Iron, Nickel and Cobalt is called Magnet.

Q.4. What is Magnetism?
Ans. The power of attracting small pieces of Iron is called Magnetism.

Q.5. Give examples of three magnetic substances?
Ans. Iron, Nickel and Cobalt.

Q.6. What is Mixture?
Ans. When two or more substances combine together in any ratio and no new substance is obtained then the substance formed is known as a mixture.

Q.7. What is the formula of Alum?
Ans. The Formula of Alum is K2SO4, Al2(SO4)3.24H20

Q.8. Is Sand and element or a Compound?
Ans. Sand is a Compound.

Q.9. What is the Chemical name of Sand?
Ans. The Chemical name of sand is Silicon Dioxide.

Q.10. Is Alum an element or a Compound?
Ans. Alum is Compound.

Q.11. What is the difference between a Mixture and a Compound?
Ans.
MIXTURE In Mixture consitituent are present in any ratio and its properties are not totally different from its constituents.
COMPOUND In Compound the constituents are always present in a fixed ratio and the properties of compound are totally different from its constituents.

Q.12. How many elements are present in Alum?
Ans. There are five elements present in Alum.

Q.13. What are the names of the elements present in Alum?
Ans. The elements present in the Alum are
1. Potassium
2. Sulphur
3. Oxygen
4. Aluminium
5. Hydrogen
Q.14. Is Iron an element or Compound?
Ans. Iron is an element.

Q.15. Which element are present in Sand?
Ans. Silicon and Oxygen are present in the sand.

Q.16. What is the symbol of Iron?
Ans. The symbol of Iron is Fe.

Q.17. What is Alum?
Ans. Alum is a double salt.

Q.18. What is an element?
Ans. An element is a simple substance which cannot be further divided into simpler substances by ordinary Chemical Process.

Q.19. What is a Compound?
Ans. A Compound is composed of atoms of two or more than two elements.

Q.20. Define Mixture?
Ans. Mixture is that substance which is composed of two or more substances in which there is no Chemical bonding and the substances have been mixed in variable proportions.

Q.21. Give five examples of Element and Compounds?
Ans. Examples of Elements
1. Mercury
2. Oxygen
3. Aluminium
4. Sulphur
5. Iron
Examples of Compounds
1. Water
2. Calcium
3. Sulphate
4. Sugar
5. Baking Soda
6. Ammonium Chloride

Q.23. What is Filtration?
Ans. The process by which Insoluble impurities are removed from liquida is called Filtration.

Q.24. What are uses of Filtration?
Ans. Filtration is used in many industries for removing solid paticles from their liquid components e.g. muddy water is purified by means of filtration when suspended material is removed.

Q.25. What is Distillation?
Ans. Distillation is that process in which a liquid is converted into vapours and these vapours on condensation from liquid again.

Q.26. What is Distillate?
Ans. The vapour which is condensed into liquid is called Distillate.

Q.27. What is Filtrate?
Ans. The pure liquid obtained after filtration is called Filtrate.

Q.28. What is Filter Paper?
Ans. The porous paper used in the process of filtration is called Filter Paper.

Q.29. What is Residue?
Ans. The insoluble substance obtained on the filter paper is called Residue.

Q.30. What do you mean by Evaporation?
Ans. The process of changing of liquid into vapour at all temperature is called Evaporation.

Q.31. What are the uses of Distillation?
Ans. USES OF DISTILLATION The process of distillation is used to recover a solvent from solution. In industries the distillation is used in water distilleries for manufacture of Distilled water.
Q.32. How are the magnetic substances removed?
Ans. The magnetic substances are removed with the help of a magnet.

Q.33. How will you remove insoluble impurities?
Ans. The insoluble impurites are removed by Filtration.

Q.34. How are the Crystalline subtances removed?
Ans. Crystalline substances are removed by evaporation or Crystallization.

Q.35. Why does the sand remain on filter paper?
Ans. The sand is insoluble so if remains on the filter paper.

Q.36. What is Solute?
Ans. Any substance which dissolves in some other substance is called Solute
OR
The component of solution which is present in smaller amount is called the solute.

Q.37. What is Solvent?
Ans. Any substance which can dissolve a substance to form homogeneous mixture is called a solvent.
OR
The component of the solution present in greater amount is called the solvent.




EXPRTIMENT NO. 3


Viva Voce
Q.1. What do you understand by by Boiling?
Ans. Boiling is defined as the state at which the liquid starts changing into vapour at fixed temperature.
OR
Boiling is the state of liquid at which the vapour pressure of the liquid becomes equal to atmospheric temperature.

Q.2. What is Boiling Point?
Ans. That fixed temperature at which the liquid starts boiling is known as Boiling Point.

Q.3. What do you understand by "Melting"?
Ans. That state of solid at which it starts changing into liquid without change of temperature is called Melting.
Q.4. What is melting point?
Ans. The fixed temperate at which a solid melts or changes into liquid is called Melting Point.

Q.5. Is Benzene or Ethyl Alcohal an Inorganic Compount?
Ans. No! It is an Organic Compound.

Q.6. What is the formula of Benzene or Ethyl Alcohal?
Ans. The formula of Benzene is C6H6 and formula of Ethyl Alcohal is C2H5OH.

Q.7. Is wax an Inorganic Compound?
Ans. No! The wax is an Organic Compound.

Q.8. What is the effect of pressure on melting point?
Ans. The melting point of that substance which expands on freezing decreases with pressure i.e. its melts at lower temperature.

Q.9. What is the effect of pressure on melting point in case of those substances which contract on freezing?
Ans. By increasing the pressure the melting point of those substances which contract on freezing is increased.

Q.10. What do you understand by Evaporation?
Ans. The change of liquid into vapour at all the temperature is called Evaporation.
Q.11. Is Benzene an element or a compound?
Ans. Benzene is a compound.

Q.12. Which elements are present in Benzene?
Ans. Carbon and Hydrogen are present in Benzene.

Q.13. What is the effect of pressure on boiling point?
Ans. If the pressure is increased then the boiling point increases.

Q.14. What is the effect on melting point of Wax if pressure is increased?
Ans. The Melting point of wax rises with increase of pressure because wax contracts on freezing.

Q.15. What are the factors on which rate of evaporation depends?
Ans. Rate of evaporation depends upon the following factors.
1. Nature of liquids
2. Area of Surface
3. Temperature of Liquid
4. Temperature of Air
5. Dryness of Air
6. Motion of Air
7. Pressure

Q.16. What is the Latent Heat of Fusion of Ice?
Ans. Amount of Heat taken by 1 Kg of Ice at its melting point in changing into water at the same temperature is called Latent Heat of Fusion of Ice.

Q.17. Why does temperature remain constant at boiling point of liquid?
Ans. At this stage the heat is utilized for converting liquid into vapours so the temperature remains constant.

Q.18. What is the boiling point of pure water?
Ans. The boiling point pure water is 100oC at a pressure of 760 m.m.

Q.19 Does the boiling point of liquid depend upon the pressure of atmosphere?
Ans. Yes! The boiling point of liquid depends upon atmospheric pressure.

Q.20. What is the difference between Boiling and Evaporation?
Ans. Boiling Boiling is a rapid change of liquid into vapour and takes place at definite temperature. Moreover the boiling takes place throughout the mass of liquid.
Evaporation Slow change of liquid into vapour at all the temperatures is called Evaporation. It takes place at the surface of liquid.

Q.21. What is effect of height on the boiling point of liquid?
Ans. With increase of height the boiling point of liquid decreases.

Q.22. Why should we stir the liquid during the process of heating?
Ans. The liquid should be stirred constantly for helping the liquid in maintaining uniform temperature.
Q.23. What precautions should be taken in determination of melting point of wax?
Ans. The following precautions should be taken in determination of melting point of wax.
1. The Capillary tube should be so long that its upper part should be out of beaker.
2. The bath should b heated slowly with constant stirring.
3. Reading of Thermometer should be taken when steady stream of bubble starts to appear.



EXPERIMENT NO. 4

Viva Voce
Q.1. What is solute?
Ans. The constituent present in smaller amount in the solution is called solute. Or Any substance which dissolves in some other substance is called a Solute.
Q.2. What is Solvent?
Ans. Any substance which can dissolve a substance to form a homogeneous mixture is called a Solvent.
OR
The component of the solution which is present in greater amount is called the solvent.

Q.3. What is Solution?
Ans. A homogeneous mixture of two or more substances is called solution.

Q.4. How many classes of solutions are there?
Ans. There are nine classes of Solution.
SOLUTE
Gas
Gas
Gas
Liquid
Liquid
Liquid
Solid
Solid
Solid
SOLVENT
Gas
Liquid
Solid
Gas
Liquid
Solid
Gas
Liquid
Solid

Q.5. Give an example of Solution of Gas in Gas?
Ans. Air.

Q.6. Give an example of Solution of Gas in Liquid?
Ans. Water Vapours in Air.

Q.7. Give an example of Solution of Solid in Gas?
Ans. Sodium in Nitrogen Gas.

Q.8. Give an example of Solution of Liquid in Gas?
Ans. Oxygen or Carbon Dioxide in water.

Q.9. Give an example of Solution of Liquid in Liquid?
Ans. Alcohal in water or Bromine in Carbon Disulphide.

Q.10. Give an example of Solid in Liquid?
Ans. Salt in water, Sugar in water, Sulphur in Carbon Disulphide.

Q.11. Give an example of Gas in Solid?
Ans. Hydrogen in Palladium.

Q.12. Give an example of Solution of Liquid in Solids?
Ans. Mercury in Sodium.

Q.13. Give an example of Solution of Liquid in Solids?
Ans. Alloys like Brass, Bronze.

Q.14. What is Isomorphous mixtures?
Ans. Solid Solutions are sometimes called Isomorphous Mixtures because the constituents can be separated on crystallization.

Q.15. What is Solubility?
Ans. The Solubility of a substance can be defined as the amount of the substance that can be dissolved by 100 grams of the solvent at a particular temperature mathematically it can be expressed as: Solubility = Weight of Solute in gm / Weight of Solvent in gm x 100

Q.16. What is Saturated Solution?
Ans. A Solution that can't dissolve any more of the solute at a mix temperature is called a Saturated Solution.

Q.17. What are the factors which effect the solubility?
Ans. (A) Pressure does not effect the solubility too much in case of a solid and liquid solutions. But the solubility is considerably effected if a gas is being dissolved in a liquid. As the pressure increases at constant temperature more and more gas dissolves.
(B) Solubility of a Gas in Liquids usually decreases with increase in temperature. Owing to this reason when we heat the water, the air bubbles come out.
(C) Solubility of solids usually increases with increase in temperature. Example KNO3 and KBr.
(D) Those solids which dissolve with the liberation of heat usually show decrease in solubility on increasing the temperature.

Q.18. What is Morality?
Ans. Molarity is the number of moles of Solute present in one litre of the solution. For
Example a molar solution is that one which contains one mole of solute dissolved per litre.

Q.19. What is Molality?
Ans. Molality is the number of moles of solute dissolved in one kg (1000gm) of solvent. Hence one molal is that solution which contains one mole of the solute in 1 kg (1000 gm) of Solvent.

Q.20. What is standard Solution?
Ans. The solution whose concentration is already known is called Standard Solution.

Q.21. What is Normal Solution?
Ans. A Normal Solution is that solution which is prepared by dissolving in gm. Equivalent of the substance and making it upto one litre (1000 C.C) of the solution.

Q.22. What is Gram Equivalent Weight?
Ans. The Gram Equivalent Weight of a substance i.e. (Equivalent Weight expressed in Gram) is
that weight which corresponds to (i.e. combines with or displaces) one gram of Hydrogen or
eight gm of Oxygen or 35.5 gm of Chlorine.

Q.23. What is Normality?
Ans. The gram equivalents of solute present in one litre of the solution is known as its
Normality.
Normality = Gm.Equivalent of Solute / Volume of Solution in Litre
Q.24. What do you understand by the strength of a Solution?
Ans. The quantity of a substance present in any known volume of the solution is called the
strength of a solution.

Q.25. How is the strength of a solution is determined?
Ans. Normality = strength per litre of a solution / Equivalent weight of a substance.

Q.26. What do you understand by "Basicity" of Acid?
Ans. The number of the replaceable or ionisabale Hydrogen atom in the molecule of an acid is
called its Basicity.

Q.27. What do you understand by "Acidity" of Base?
Ans. The number of "Hydroxyl Ions" which a molecule of base can provide is called Acidity of
Base.

Q.28. How do you determine the Equivalent weight of an Acid?
Ans. Equivlent weight of an Acid = Molecular Weight / Basicity.

Q.29. How do you determine the Equivalent weight of a base?
Ans. Equivalent weight of a Base = Molecular Weight / Acidity

Q.30. What are Monoacid Bases, Diacid Bases and Triacid Bases?
Ans. Monoacid Bases The bases which contain Hydroxyl are called Monoacid Bases e.g.
NaOH.
Diacid Bases The bases which contain two hydroxyl ion are called Diacid Bases e.g. Ca
(OH)2.
Triacid Bases The bases which contain three Hydroxyl Ions are called Triacid Bases
e.g. Al(OH)3.

Q.31. What are Monobasic Acids, Dibasic Acids and Tribasic Acids?
Ans. Monobasic Acids The acids which have only one replaceable Hydrogen atom are known
as Monobasic Acids.
Dibasic Acids The acids which have two replaceable Hydrogen atoms are known as Dibasic
Acids.
Tribasic Acids The acids which have three replaceable Hydrogen atoms are known as
Tribasic Acids.e.g. H3PO4.

Q.32. What do you understand by concentration of solution?
Ans. The amount of solute present in a given amount of solvent is called concentration of
solution.

Q.33. What do you mean by 0.1 m Solution?
Ans. It means 0.1 or 1/10 (One tenth part of molecular weight of a substance is dissolved in
one litre solution). It is also known as Deci-molar solution.

Q.34. What do you understand by "Gram Atom"?
Ans. The atomic weight of an element expressed in grams is called Gram Atom or Gram Atomic
Weight.

Q.35. What do you mean by Molecular weight?
Ans. The molecular weight of an element or a compound means the total weight of all atoms
present in the element or compound (or it is the formula weight of the element or compound).

Q.36. What is a Mole?
Ans. A mole is defined as the atomic weight or molecular weight of the substance expressed
in grams. In other words, a "Gram Atom" or a "Gram Molecule" of an element or a compound is
called a Mole.

Q.37. What is IM solution of Oxalic Acid?
Ans. If one litre solution of Oxalic Acid contains one mole or 126 gm of Oxalic Acid then
such solution is called IM solution.

Q.38. How will you calculate the molecular weight of the following. N2, Cl2, H2, H2SO4,
HNO3, NaOH and KOH.
Ans.
N2 = 2 x 14 = 28
Cl2 = 2 x 35.5 = 71
H2SO4 = 2 x 1 + 32 + 4 x 16
= 2 + 32 64 = 90
HNO3 = 1 + 14 3 x 16
= 1 + 14 + 48 = 68
NaOH = 23 + 16 1 = 40
KOH = 39 + 16 + 1 = 56

Q.39. What is the Molecular Formula of Oxalic Acid?
Ans. (COOH)2.2H2O

Q.40 What is the Molecular Weight of Oxalic Acid?
Ans. (COOH)2.2H2O
= [12 + 16 + 16 + 1] x 2 + [2 + 16]
= (45)2 + 2(18)
= 90 + 36
= 125

Q.41 How will you prepare Decimolar Solution?
Ans. A Decimolar Solution (0.1 m) of any substance can be prepared by dissolving one tenth
part (1/10) of gram molecular weight per litre of solution.

Q.42. What is 1M NaOH Solution?
Ans. IM Solution of NaOH = 1 mole i.e. 40 gm per 1000 ml. (1 litre) solution.

Q.43. What is 0.5 m solution of Oxalic Acid?
Ans. If one litre of solution of Oxalic Acid contains on mole or 126 gm of Oxalic Acid then
such solution is called 1M Solution.

Q.44. What is formula for calculating the number of mole in given weight of the
substance?
Ans. Number of Moles = Gram Weight / Molecular Weight.

Q.45. How is the concentration of a solution expressed?
Ans. The concentration of a solution can be expressed by the following
1. Molarity (m)
2. Molality (m)
3. Normality (N)

Q.46. What is meant by Hygroscopic Substance?
Ans. The substance which observes moisture from air is called Hygroscopic substance.

Q.47. What is Volume?
Ans. Space occupied by a substance is called its Volume.

Q.48. What is the unit of Volume?
Ans. The unit of Volume is litre.

Q.49. What is Litre?
Ans. The space occupied by 1 Kg of water at 4oC is called Litre.

Q.50 What is Normal Solution?
Ans. Solution obtained by dissolving are gram equivalent of a substance in one litre of
solution is called Normal Solution.

Q.51. What is one Milli-Litre?
Ans. One Milli-Litre is 1/1000 the part of a Litre.

Q.52. What is meant by N/10 Solution?
Ans. N/10 solution is a deci normal solution and is obtained by dissolving one tenth of gram
Equivalent substance is one litre of solution.

Q.53. How much Oxalic Acid is required for IM solution of 1000 ml?
Ans. 1 mole of Oxalic Acid i.e. 126 gm is required in 1000 ml solution.

Q.54. How much Oxalic Acid is required for preparing 1M solution in 250 ml?
Ans. In 1000 ml solution of 1M we require 126 gm of Oxalic Acid. In 250 ml solution of 1M we
require 250/1000 x 126 = 31.5 gm of Oxalic Acid.

Q.55. How much Oxalic Acid is required in .05 solution of 500 ml?
Ans. .05 x 126 = 5/100 x 126 = 6.3 gm.

Q.56. How much Oxalic Acid is required for preparing .05 solution of 500 ml?
Ans. 500 / 1000 x 126 x .05 = 31.5 gm of Oxalic Acid is required.

Q.57. What is relation between Mole and Gram Atom?
Ans. Mole indicates a definite number i.e. 2,4 or 6 etc. But on the other hand Gram atom
indicates a definite quantity i.e. 8.0 gm, 16 gm or 35.5 gm.

Q.58. What is the relation between Mass and Weight of the substance?
Ans. Weight = mass x acceleration due to gravity i.e. W=mg.

Q.59. Does the balance give us the mass of the substance?
Ans. The balance give us the mass of the substance.

Q.60. What kind of Lever is the Physical Balance?
Ans. It is the first kind of Lever.

Q.61. What is value of 530 mg into gm?
Ans. 530 mg = 530 gm.
Q.62. What is gram molecular weight?
Ans. The weight in gm of a molecular is called gram molecular weight.

Q.63. What is Avogadro's Number?
Ans. The number of atoms in one gram or number of molecules in one mole is called Avogadro's
Number. Its value is 6.02 x 1023.

Q.64. Define Atom?
Ans. Atom is the smallest particle of an element.

Q.65. What is a Molecule?
Ans. Smallest particle of the element or compound which can exist in free state is called a
molecule.

Q.66. What is the function of screws of the base of Physical Balance?
Ans. These screws are known as Levelling Screws as they are used to keep the balance in
horizontal position.

Q.67. How do we know that the balance is in horizontal position?
Ans. We can know it by Plumb line or Spirit Level.

Q.68. What is the function of Scale?
Ans. When beam is raised the pointer moves on the scale and if it moves equally on both
sides the balance is adjusted.

Q.69. How do we adjust the balance?
Ans. We adjust the balance with the help of two adjoining screws at the end of the beam.

Q.70 Why do we place the weight generally on the right hand side?
Ans. It is due to the reason that most of us work with the right hand and it is most
convenient.

Q.71. Should we add or remove the weight when the beam is raised?
Ans. No! The beam must be lowered, otherwise there will be jerk and the adjustment will be
disturbed.

Q.72. What is an acid?
Ans. Acids are compound whose solution in water exhibit the following properties.
1. They have a sour taste.
2. They turn blue litmus red.
3. They give Hydrogen when treated with metal.
4. They react with metal oxides and their hydroxides forming salt and water.

Q.73. What is Arhenius Definition of an Acid?
Ans. According to Arhenius "Acids are those substances which produce H ions in aqueous
solutions.

Q.74. What are Weak Acids?
Ans. Acids which ionise to small extent in water are called Weak Acids.

Q.75. What are Strong Acids?
Ans. Those acids which ionise completely are called strong Acids. e.g. HCl, H2SO4, HNO3.

Q.76. What are Hydronium Ions?
Ans. Free H+ ions do not exist freely in water and so they are associated with water and
form H3O (Hydronium Ions)

Q.77 What is Lowry and Bronsted definition of Acid?
Ans. Lowry and Bronsted defined an acid as a substance which tend to lose protons or Acids
are protons Donors.

Q.78. What is Lewis definition of an Acid?
Ans. It has been observed that donation of Hydrogen Ion in an acid is not essential since an
acid may not even possess an Hydrogen atom in its molecule. Hence Lewis an American
scientist proposed generalised concept of Acid.



EXPERIMENT NO. 5


Viva Voce
Q.1. What is the Chemical name of Common Salt?
Ans. Sodium Chloride.

Q.2. What is the Chemical Formula of Sodium Chloride?
Ans. NaCl.

Q.3. What is Solute?
Ans. The constituent present in larger amount in solution is called Solvent.

Q.4. What is Solvent?
Ans. The constituent present in larger amount in solution is called Solvent.

Q.5. What is Solution?
Ans. The homogeneous mixture of solute and Solvent is called SOlution.

Q.6. What is Solubility?
Ans. The maximum quantity of a solute dissolved in 100 gm. of solvent at a particular
temperature is called the solubility of the solute.

Q.7. What is the name of that substance which dissolve in some other substance?
Ans. It is called Solute.

Q.8. What is the name of that substance which can dissolve other substance?
Ans Any substance which can dissolve a substance to form a homogeneous mixture is called a
Solvent.

Q.9. What is the name of homogeneous mixture of two substances?
Ans. It is called Solution.

Q.10. What is Suturated Solution?
Ans. A solution that can't dissolve any more of the solute at a fixed temperature is called
a Saturated Solution.

Q.11. What are the factors which effect the Solubility?
Ans.
(a) Pressure does not effect the solubility too much in case of a solid and liquid solution.
But the solubility is considerably effected in case of a gas is being dissolved in a liquid.
As the pressure increases at constant temperature more and more gas dissolves.
(b) Solubility of a gas in liquids usually decreases with increase in temperature, owing to
the reason that when we heat the water, the air bubbles come out.
(c) Solubility of Solids usually increases with increase in temperature. Example KNO3 and
KBr.
(d) Those solids that dissolve with liberation of heat usually show decrease in solubility
on increasing the temperature.

Q.12. What is the difference between a Mixture and Solution?
Ans. Mixture A heterogeneous substance in which the constituent can be seen lying side
by side is called a Mixture. Therefore it consists of two or more than two phases.
Solution Homogeneous mixture of two substances is called solution. It is uniform
throughout. Hence it consists of only one phase. In a solution the substances are mixed. So
thoroughly that something new appears to be formed.

Q.13. What is Unsaturated Solution?
Ans. By unsaturated solution we mean that solution in which some more quantity can be
dissolved at that temperature.

Q.14 What is the meaning of Solubility at a particular temperature?
Ans. By solubility at a particular temperature, we mean that quantity of substance (solute)
which is present in 100 gm of solvent at that temperature.

Q.15. What do you mean by Mother Liquor?
Ans. Saturated solution from which the crystals have been removed is called Mother Liquor.

Q.16. How many types of mixture are there?
Ans. There are two types of mixture.
1. Homogeneous Mixture
2. Heterogeneous Mixture

Q.17. Why do you call a solution a Homogeneous Mixture?
Ans Solution is called Homogeneous mixture because it contains one phase only.

Q.18. Why do you heat the solution when the substance is dissolved in the solvent?
Ans. By heating the solubility increases and more substance can be dissolved.

Q.19. What is Evaporation?
Ans. It is the process of change of liquid into vapours at all temperatures.
Q.20 What is the name of that solution in which more of the solute can be dissolved at
the same temperature?
Ans. Unsaturated Solution.

Q.21. What is the formula of Solubility?
Ans. Solubility = Weight of solute / Weight of solvent x 100\

Q.22 What is the difference between Evaporation and Boiling ?
Ans. Evaporation Evaporation takes place on the surface of liquid and at all the
temperature.
Boiling Boiling takes place at a fixed temperature and throughout the liquid.

Q.23. What is the Boiling Point of water at Sea Level?
Ans. The Boiling Point of water at Sea Level is 100oC.

Q.24. What is the relation between Boiling Point and Vapour Pressure?
Ans. Temperature at which vapour pressure of liquid becomes equal to atmospheric pressure is
called Boiling Point.

Q.25. What do you understand by Boiling Point?
Ans. That fixed temperature at which the liquid changes into vapour or the vapour pressure
becomes equals to atmospheric pressure is called Boiling Point.

Q.26. Why is it so that sugar is insoluble in Petrol?
Ans. A solution is not formed if the attractive forces between the components of solute are
greater than attractive forces between the solute and solvent.

Q.27. When is it easier to form a solution?
Ans. It is easier to form a solution if attractive forces in components of solute are less
than the attractive forces between the solute and the solvent.

Q.28. What are Isomorporhous Mixture?
Ans. Solid solutions are sometimes called Isomorphous Mixtures because the constituents of
such solution can be separated on Crystallisation.

Q.29. How many classes of Solution are there?
Ans.
1. Gas in gas
2. Gas in liquid
3. Gas in solid
4. Liquid in gas
5. Liquid in liquid
6. Solid in liquid
7. Liquid in solid
8. Solid in solid

Q.30. Give an example of Gas in Gas
Ans. Air

Q.31. Give an example of solution of liquid in gas?
Ans. Water vapour in air.

Q.32. Give an example of solution of solid in gas?
Ans. Iodine in Nitrogen Gas.

Q.33. Give an example of solution of gas in liquid?
Ans. Oxygen or Carbon Dioxide in Water.

Q.34. Give an example of solution of liquid in liquid?
Ans. Alcohal in water or Bromine in Carbon Disulphate.

Q.35. Give an example of solution of solid in liquid?
Ans. Salt in water, Sugar in water.

Q.36. Give an example of Gas in Solid?
Ans. Hydrogen in Pladium.

Q.37. Give an example of solution of liquids in solids?
Ans. Mercury in Sodium.

Q.38. Give an example of solution of solid in solid?
Ans. Alloys like Brass and Bronze.

Q.39. What are the main precautions in this experiment?
Ans. The following precautions should be kept into consideration.
1. Physical Balance should be adjusted before the start of practical.
2. Weights should be placed on the right hand pan.
3. During determination of weight the shutter should remain closed.
4. The mass of the China Dish should be determined after cooling.

Q.40. Which kind of lever is the Physical Balance?
Ans. First kind of Lever.

Q.41. Which is heavier 20 gm of Iron or 20 gm of Cotton?
Ans. Both will have the same weight.

Q.42. What do you understand by the beam of a Physical Balance?
Ans. The beam is a horizontal metal frame work capable of turning freely with very little
friction about an "Agate Knife Edges"at its centre called Fulcrum.

Q.43. How many knife edges are there in the Physical Balance?
Ans. There are three knife edges. One at the middle and two at the end.

Q.44. What are the important parts of Physical Balance?
Ans. The important part of Physical Balance are given below.
1. Beam
2. Adjusting Screws
3. Knife Edge
4. Stump
5. Pan
6. Vertical Pillar, Pointer Scale
7. Plumb Line (or Spirit Level)
8. Levelling Screws
9. Knob.
Q.45. What is the purpose of the Plumb Line?
Ans. To make the pillar vertical and base horizontal.

Q.46. What should be done if the plumb line is broken?
Ans. In such case spirit level is used to test the level of the base of the Physical
Balance.

Q.47. Why is it advised that when Balance is not in use should not be raised too much?
Ans. The sharpness of the knife edge is preserved.

Q.48. Why do we place the Physical Balance in a glass case?
Ans. It is kept in a glass case to prevent it from being disturbed by wind when weighing is
going on and from being contaminated with acid fumes and moisture.

Q.49. What are the conditions to be satisfied by a good balance?
Ans. A good balance must satisfy the following conditions.

Q.50. What are Fractional Weights?
Ans. Milligram weights which are made up of heavy aluminium or then platinum foils are known
as "Fractional Weights".

Q.51. On the Specific Gravity, 25 ml, 50 ml and 20oC is written. What do you mean by
that?
Ans. 25 ml and 50 ml means 25 millilitre, 50 millilitre which indicates the volume of the
bottle. 20oC is the temperature at which the volume of the particular bottle is 25 ml or 50
ml.

Q.52. What is Physical Balance?
Ans. It is the instrument for comparing the mass of an object with a known mass.

Q.53. What is the Principal of Balance?
Ans. It works on the Principles of First Kind of Lever.

Q.54. Convert 865 mg in gram.
Ans. 865 mg = .865 gm.

Q.55.How many milligrams are there in one gram?
Ans. 1000 mg = 1 gm.

Q.56. How many ml are there in one litre/
Ans. 1000 ml = 1 litre.

Q,57. What is the effect of temperature on the solubility of substance?
Ans. The solubility of a substance increases by increase of temperature.

Q.58. What is the effect of pressure on the boiling point of a liquid?
Ans. Boiling Point is lowered when the pressure is decreased and it is increased when the pressure is raised.

Q.59. At what temperature will the water if the pressure is reduced from 760 mm to 24 mm of Hg?
Ans. The water boils at 25oC if the pressure is reduced from 760 mm to 24 mm of Hg.




EXPERIMENT No. 6


Viva Voce
Q.1. What is an Acid?
Ans. Acids are compounds whose solution in water exhibit the following properties.
1. They have a sour taste.
2. They turn blue litmus red.
3. They give hydrogen when treated with metal.
4. They react with metal oxides and their hydroxides forming salt oxide and water.

Q.2. What is Arhenius definition of an Acid?
Ans. According to Arhenius. Acids are those substances which produce H ions in aqueous
solution.

Q.3. What is Ionization?
Ans. The process of formation of H ions from acids is known Ionization.

Q.4. What are Strong Acids?
Ans. Those acids which ionize completely are called Strong Acids. Examples HCl, H2SO4, HNO3.

Q.5. What are Weak Acids?
Ans. Acids which ionise to small extent in water are called Weak Acids.

Q.6. What are Hydronium Ions?
Ans. Free H ions do not exist freely in water and so they are associated with water and form
H3O (Hydronium Ions)

Q.7. What is Lowry and Bronsted definition of Acid?
Ans. Lowry and Bronsted defined an acid as a substance which tends to lose Protons or Acids
are Protons Donors.

Q.8. What is Lewis definition of an Acid?
Ans. It has been observed that donation of Hydrogen Ion in an acid is not essential, since
an acid may not even possess as Hydrogen atom in its molecule. Hence Lewis an American
Scientist proposed generalised concept of acid. Acid is an electron acceptor.
Example. Aluminium Chloride acts as Lewis Acid because its molecule is short of two
electron.

Q.9. In which substances do the following acids occur? Citric Acid, Tartaric Acid, Acetic
Acid, Lactic Acid, Formic Acid.
Ans.
Citric Acid -------> Lemon
Tartaric Acid -----> Grapes, Tamarind
Acetic Acid -------> Vinegar
Lactic Acid -------> Fermented milk
Formic Acid -------> Sting of bees, Wasp

Q.10. What is the effect of Acid on the following? Blue Litmus, Methyl Orange,
Phenolphtalene.
Ans.
Blue Litmus -------> Red
Methyl Orange -----> Red
Phenolphtalene ----> No effect.

Q.11. What happen when acid reacts with base?
Ans. Acids and Bases neutralize each other then salt and water are formed.
Hcl + NaOH -------> NaCl + H2O
(Acid) (Base) (salt) (Water)

Q.12. What is Basicity of Acid?
Ans. The number of replaceable or ionizable Hydrogen atoms present in the molecule of Acid
indicates its Basicity. Example
HCl -------> Monobasic Acid
H2SO4 -----> Dibasic Acid
H3PO4 -----> Tribasic Acid

Q.13. What is Concentrated Acid?
Ans. Pure Acid containing no water is called Concentrated Acid.

Q.14. What is Dilute Acid?
Ans. Acid containing large amount of water is called Dilute Acid.

Q.15. Does the acid react with Gold and Silver?
Ans. No.

Q.16. What is the effect of acid on the Skin?
Ans. Strong Acids Corrode the Skin.

Q.17. What is the percentage of HCl in the gastric juice?
Ans. 0.2 to 0.4%

Q.18. What is the function of HCl in the Human Body?
Ans. It is essential for the proper digestion of food.

Q.19. What is the definition of Base according to Arhenius?
Ans. According to Arhenius a base is a substance which in aqueous solution provides Hydroxyl
Ions (OH) Example NaOH, Ba(OH)2, Al(OH)3
NaoH <-------> Na+ + OH
Ba(OH)2 <-------> Ba++ + 2OH-
Al (OH)3 <-------> Al+++ + 3 OH-
Q.20 What is the definition of base according to Lowry and Bronsted?
Ans. A base is a proton acceptor.

Q.21. Is it essential that an acid should donate H+ ions?
Ans. Donation of Hydrogen ions in an acid is not essential since an acid may not even
possess a Hydrogen Atom in its molecule.

Q.22. What is generalised definition of Base according to Lewis?
Ans. Base is an electron donor.

Q.23. What are the general properties of Base?

Ans.

1. They have a bitter taste.

2. They have slippery touch.

3. They conduct electricity.

4. They react with indicators

Red Litmus -------> Blue

Phenolphtalene ---> Pink

Methyle Orange ---> Yellow

Turmeric Paper ---> Brown

5. Combine with fats to form Soaps.

6. They react with bases to form salt and water.

NaOH + HCl -------> NaCl + H2O

Q.24. What is Strong Base?
Ans. A base which ionises completely is called Strong Base e.g. NaOH, KOH.

Q.25. What is Weak Base?
Ans. A base which contain small amount of water is called Weak Base.

Q.26. What is Concentrated Base?
Ans. A base which contains small amount of water is called Concentrated Base.

Q.27. What is Dilute Base?
Ans. That base which contain large amount of water is called Dilute Base.

Q.28. What is an Alkali?
Ans. A base which is highly soluble in water is called an Alkali. It ionises nearly
completely e.g. NaOH, KOH.

Q.29. Do you think that every base is an Alkali?
Ans. No.

Q,30. Do you think Alkali is a base?
Ans. Yes.

Q.31. What is the Acidity of Base?
Ans. The number of Hydroxyl Ions which a molecule of base can provide is called Acidity of
the base.
NaOH -------> Monoacid Base
Ba(OH)2 ----> Diacid Base
Al(OH)3 ----> Triacid Base

Q.32. Give examples of Weak Acids?
Ans. Acetic Acid (CH3COOH), Carbonic Acid (H2CO3).

Q.33. Does Acetic Acid ionise completely?
Ans. No. it ionises partially.

Q.34. Give example of Weak Base?
Ans. NH4OH (Ammonium Hydroxide)

Q.35. What is One Mole?
Ans. Molecular Weights of a substance in gram is termed 1 Mole.

Q.36. By how much amount of base, one mole of acid can be neutralised?
Ans. One Mole of Base is required.
Q.37. What is Neutralization?
Ans. Neutralization is simply a reaction between Hydrogen Ion of an Acid an Hydroxide Ion of
the base to form water. In this reaction salt is also produced which remains in the solution
as Ion.

Q.38. What is meant by "Titraton"
Ans. Titration is the process of adding one solution from Burette in the conical flask (or
any other container containing known volume of other solution) to measure the volume of the
solution of the burette after the completion of chemical reaction between the two solutions
using indicator.
OR
Titation is the process of adding one solution from one burette to another in the conical
flask in order to determine its volume after the completion of Chemical reaction.
OR
Titration is an operation by which the strength of an unknown solution is determined by
allowing it to react with a standard solution.

Q.39. Why do you use Phenolpthalene as indicator in the experiment?
Ans. This is a titration of weak acid and a strong base. Hence Phenolphtalene is a suitable
indicator.

Q.40. What do you mean by End Point?
Ans. It is the exact stage at which the chemical reaction of the titration solutions is just
completed.

Q.41. Why alkali is taken in the burette when Phenolphtalene is used as an indicator?
Ans. The appearance of a pink colour at the end point can be observed easily. So it is
comparatively better than the disapperance of colour when acid is used in the burette.

Q.42. What are the Ionic definitions of Acids and Bases?
Ans. By the ionic point of view the acids are substances which give Hydrogen Ion (H+) in
solution while bases are substances which give Hydroxyl Ion (OH-) in solution.

Q.43. What is the formula of Oxalic Acid?
Ans. The formula of Oxalic Acid is
COOH
|
COOH

Q.44. What substances are present in the conical flask after neutralization?
Ans. Salt and water are present in the conical flask after neutralization.

Q.45. How will you obtain salt from the conical flask?
Ans. Salt can be obtained by evaporation.

Q.46. What do you undertand by the words 10 ml and 20oC written on the pipette?
Ans. It means that 20oC temperature, the pipette can contain 10 ml of liquid upto the given
mark.

Q.47. How will you represent the reaction of Oxalic Acid with Sodium Hydroxide by
Chemical equation?
Ans.
COOH COONa
| + 2NaOH ----> | +2H2O
COOH COONa

(oxalic acid) (Sodium Hydroxide) (Sodium Formate) (Water)

Q.48. What is an Indicator?
Ans. Indicator is a substance which is added to the solution in titration process and
indicates the end point of the reaction.

Q.49. Why do you call Oxalic Acid an Acid?
Ans. Oxalic Acid is called Acid because in its aqueous solution, it gives of H+ ions and it,
turn blue litmus red.

Q.50. What is the reaction between Sodium Hydroxide and Hydrochloric Acid?
Ans.
NaOH + HCl ----------> NaCl + H2O
(SOdium Hydroxide) (Hydrochloric Acid) (Sodium Chloride) (Water)

Q.51. What are the two important indicators generally used in titration?
Ans. Phenolphtalene and Methyl Orange are the two indicators generally used in Titration.

Q.52. How many number of molecules are present in the Crystals of Oxalic Acid?
Ans. Two molecules of water are present in the crystal of Oxalic Acid (C2H2O4.2H2O)

Q.53. What name is given to the water molecules present in the Crystals of a Solid
Substance?
Ans. Water molecules of Crystallisation.

Q.54. What is the formula of Sodium Carbonate?
Ans. Na2CO3.

Q.55. What is meant by weak Alkali?
Ans. A weak alkali is that alkali which does not ionise completely and produces less number
of Hydroxyl group.

Q.56. Give the names of few Alkalies?
Ans.
1. Calcium Hydroxide
2. Barium Hydroxide
3. Sodium Carbonate
4. Sodium Bicarbonate
5. Potassium Bicarbonate

Q.57. What indicator is used in the titration between strong acid and weak alkali?
Ans. Methyl orange indicator is used between the titration of strong acid and weak alkali.

Q.58. What is the colour of Methyl orange in Acid and in Alkali?
Ans. Methyl orange gives reddish colour in acidic medium while yellow in alkaline solution.

Q.59. Give structural formula for Methyl Orange?
Ans. Methyl Orange is an Azodye. Its structural formula is given below.
______ _______
/ \ / \
SO3H \______/ N=N \_______/ N(CH3)2

Q.60. What is Litmus?
Ans. It is well known indicator for acids and alkalies. It is derivative of arcinol. It is
also extracted from Lichens.

Q.61. What is Phenolphtalene?
Ans. It is an indicator used in titration. It is prepared by heating to 120oC Phthalic
Anhydride and Phenol for about 8 hours in presence of Anhydrous ZnCl2 or Cone.H2SO4.

Q.62. Give the names of some salts?
Ans. Sodium Carbonate (Na2CO2) Sodium Chloride (NaCl) Potassium Chloride (KCl) Magnesium
Sulphate (MgSO4)

Q.63. What are the necassary precautions in this experiment?
Ans.
1. Burette and Pipette should be washed and rinsed.
2. Burette should be clamped in the stand vertically.
3. While taking reading in the burette lower meniscus should be read.
4. There should be no air bubble in the solution in burette.

Q.64. What is Standard Solution?
Ans. A solution of known strength is called a Standard Solution.

Q.65. What is a Normal Solution?
Ans. A solution containing 1 gm equivalent weight of the substance dissolved per litre of
the solvent is called a normal solution e.g. NOrmal Solution of NaOH contains 40 gm of it
dissolved in 1 litre of water.

Q.66. How can you get salt from conical flask?
Ans. We can get salt from the conical flask by the process of Evaporation.

Q.67. Why Methyl orange is used in the Titration?
Ans. It is an indicator (Complex organic compound) used in the titration of a weak base and
strong acid.

Q.68. What is a Pipette?
Ans. It has a cylindrical shape made up of a glass for measuring the volume of a liquid. It
is marked upto 10 ml to 20 ml

Q.69. What is a Burette?
Ans. It has a cylindrical shape made up of a glass used for measuring the volume of a
liquid. It is marked from 0 ml to 50 ml or 100 ml.
Q.70. While handling the burette what precautions are necassary to be observed?
Ans.
1. Burette should be clamped vertically
2. Lower meniscus of liquid layer should be noted.
3. Remove the air bubbles before starting experiment.
4. Fill it with the help of funnel.

Q.71. What is Pilot Reading?
Ans. The first reading which is obtained after end point.

Q..72. What do you mean by "End Point"?
Ans. That stage at which the Chemical reaction of titration solution just complete.

Q.73. What is Litmus Dye or Litmus Paper?
Ans. It is a dye or Organic compound which is obtained from a plant and which is used as an
indicator as it turns red with acid and red litmus turns blue with base.

Q.74. How do we rinse the burette?
Ans. Wash the burette with water and afterwards rinse with the solution which will be poured
in it.

Q.75. How do you decide that Neutralization is complete?
Ans. Neutrazilation is complete when the single drop of NaOH (Sodium Hydroxide) is added due
to which pink colour is formed.

Q.76. When will you use Methyl Orange as indicator?
Ans. Methyl Orange is used as an indicator for the titration of Strong Acid and Weak Alkali.

Q.77. How is the end point indicated?
Ans. It is indicated by light pink colour.

Q.78. What does light pink colour indicate?
Ans. It shows that neutralization is complete.

Q.79. How do you take the last drop of acid from the Pipette?
Ans. We close the open end of the Pipette with the finger and hold the bulb in the hand,
then the air in the bulb expands due to heat of the hand and forces the last drop out.

Q.80. Which meniscus will you note while taking down the reading of the burette?
Ans. The Lower meniscus.

Q.81. Why do you note lower meniscus?
Ans. In case of colourless liquid lower meniscus is noted and in case of coloured liquid
upper meniscus is noted.

Q.82. How should we read the graduations?
Ans. We put on a piece of white paper on the opposite side so that level of liquid is easily
visible.

Q.83. Which indicator will be used for titration in the following cases?
1. Weak Acid against Strong Alkali
2. Strong Acid against Weak Alkali
3. Strong Acid againts Strong Alkali

Ans.
1. Weak Acid and Strong Base -------> Phenolphtalene
2. Strong Acid and Weak Base -------> Methyl Orange
3. Strong Acid and Strong Base -----> Phenolphtalene or Methyl Orange

Q.84. What are the conditions for a substance to be used as an indicator?
Ans.
1. It should not effect the chemical action.
2. It should give characteristics colour with one of the ions taking part in the chemical
acton.
3. A few drops of it should produce the characteristic change in colour.



EXPERIMENT NO. 7


Viva Voce
Q.1. Who discovered Carbon Dioxide?
Ans. Von Hemont in 17th Century and Joseph Black in 1728 discovered Carbon Dioxide.

Q.2. What happens when wood or any other substance containing Carbon is heated in a free
supply of air?
Ans. Carbon Dioxide is formed.

Q.3. What happens when carbon is burnt in insufficient supply of air?
Ans. Cabon Monoxide is obtained.

Q.4. What happens when Carbonates are heated?
Ans. All carbonates except Na2Co3 and K2Co3 give out Carbon Dioxide on heating.
CaCO3 -------> CaO + CO2

Q.5. What happen if Bicarbonates are heated?
Ans. Bicarbonates also on heating give pure Carbon Dioxide.
2KHCO3 ------> K2CO3 + H2) + CO2

Q.6. How will you prepare Carbon Dioxide in the laboratory?
Ans. Carbon Dioxide is prepared in the laboratory by the action of dil HCl on marble chips
or limestone CaCO3
CaCO3 + 2HCl ------> CaCl2 + H2O + CO2

Q.7. What is the molecular weight of CO2?
Ans. 44.

Q.8. Write down the name of the apparatus which are used in the experiment?
Ans. Woulffe's Bottle, Delivery Tube, Gas Jars.

Q.9. Which size of the trough is used in this experiment?
Ans. No trough is required because CO2 is highly soluble in water.

Q.10. At what angle should the delivery tube be bent?
Ans. Delivery tube should be bent twice at Right angle.

Q.11. Whether the gas is heavier or lighter than air?
Ans. Gas is heavier than air.

Q.12. How many times Carbon Dioxide is heavier than air?
Ans. It is 1.5 times heavier than air.

Q.13. By which method should the gas be collected?
Ans. It should be collected by downward displacement of gas.

Q.14. In what position should the thistle funnel be kept?
Ans. It should be kept dipped in acid so that the gas may not escape.

Q.15. If you a given a choice of acid, which acid will you prefer from sulphuric acid and
Hydrochloric acid?
Ans. We will prefer Hydrochloric acid (HCl) because of the reason that H2SO4 produce Calcium
Sulphate (CaSO4) which forms a coating over marble and further reaction is prevented.
Moreover CaSO4 forms a hard mass on the vessel and it becomes difficult to clean it. In case
of HCl Soluble CaCl2 (Calcium Chloride) is formed and so no such difficulty arises.

Q.16. How will you know that the Jar is full with gas?
Ans. A burning match stick is brought near the mouth of the Jar it gets extinguished.
OR
A moist blue litmus paper brought near the mouth of the Jar becomes red.

Q.17. What is the colour of the Gas?
Ans. It is Colourless.

Q.18. Why is it so that smoke containing CO2 is coloured?
Ans. It contains unburnt Carbon particles which remain in colloidal state in Carbon Dioxide.

Q.19. What is the smell of the Gas?
Ans. It is odourless.

Q.20. What is the taste of the Gas?
Ans. It is acidic taste.

Q.21. Is it poisonous?
Ans. NO, it is not poisonous.

Q.22. Is Carbon Monoxide poisonous?
Ans. Yes it is poisonous.

Q.23. Can you pour Carbon Dioxide like water from one Jar to another Jar?
Ans. Yes it can be poured like water from one Jar to another Jar because it is 1 1/2 times
heavier than water.

Q.24. What is the effect of pressure on the solubility of CO2?
Ans. Its solubility increases with increase of pressure.

Q.25. What are necassary precautions in this experiment?
Ans.
1. The apparatus should be air tight.
2. Dry gas jars should be used to collect Carbon Dioxide as it is soluble in water.
3. The lower end of thistle funnel should be immersed in the liquid.
Q.26. What is the Chemical name and formula of Marble?
Ans. Marble is Calcium Carbonate and its Chemical formula is CaCO3.

Q.27. Why does lime water become milky when CO3 is passed through it.
Ans. Lime water becomes milky due to formation of insoluble Calcium Carbonate.
CO2 + Ca(OH)2 --------> CaCO3 + H2O.

Q.28. What happens when Carbon Dioxide is passed in excess through lime water?
Ans. When Carbon Dioxide is passed through lime water then Calcium Carbonate is formed which
is insoluble. Later on insoluble calcium Carbonate becomes soluble due to formation of
Calcium Bicarbonate.
CO2 + Ca(OH)2 -------> CaCO3 + H2O
CO2 + CaCO3 + H2O ---> Ca(HCO3)2.

Q.29. Why is it so that a burning match stick gets extinguished when introduced in a jar
of Carbon Dioxide?
Ans. Burning Match stick gets extinguished when introduced into Carbon Dioxide jar because
this gas's non-supporter of combustion.

Q.30. What is the effect of aqueous solution of Carbon Dioxide on blue litmus paper?
Ans. Blue litmus paper becomes red because aqueous solution of CO2 is acidic.

Q.31. What are some uses of Carbon Dioxide?
Ans.
1. It is used as Fire Extinguisher.
2. It is used in the manufacturer of aerated water.
3. It is used in the preparation of Sodium Carbonate.
4. Dry Ice (Solid form of CO2) is used in medicine.

Q.32. Does Carbon Dioxide support the combustion of burning magnesium wire?
Ans. Yes, it suppurts the combustion of burning magnesium wire
Mg + CO2 ---------> MgO + C

Q.33. What is the name of the compound which is formed after the ignition of Magnesium
Wire?
Ans. White powder of Magnesium Oxide is formed.

Q.34. Why do you collect Carbon Dioxide by downward displacement of Gas?
Ans. It is due to the reason that Carbon Dioxide is heavier than air.

Q.35. Why should the apparatus be air tight?
Ans. Carbon Dioxide will escape into atmosphere, if the apparatus is not air tight.

Q.36. What are tess for Carbon Dioxide?
Ans. It extinguishes the burning match stick at once.

Q.37. What are the other methods of preparation of Carbon Dioxide ?
Ans. It may also be prepared by the following methods.
1. By the action of acids of Bicarbonate.
NaHCO3 + HCl ---------> NaCl + H2O + CO2
2. By heating Bicarbonates or Carbonates of heavy metals.
2NaHCO3 ----------> Na2CO3 + CO2 + H2O
ZnCO3 ------------> ZnO + CO2.
3. By burning carbon in air.
C + O2 -----------> CO2

Q.38. Why do you call Carbon Dioxide as "Carbonic Acid Gas"?
Ans. Carbon Dioxide is soluble in water forming Carbonic Acid which turns blue litmus red. A
Carbon Dioxide produces this acid by combining with water it is called Carbonic Acid Gas.

Q.39. Why burning Magnesium wire continues to burn in the jar of Carbon Dioxide?
Ans. Due to excessive heat of burning Magnesium Wire the Carbon Dioxide is decomposed into
Carbon and Oxygen. The oxygen combines with the magnesium forming white powder of Magnesium
Oxide and a black deposit of Carbon.
2Mg + CO2 ---------> 2MgO + C.

Q.40 What are the chemicals required in the preparation of Carbon Dioxide?
Ans. Calcium Carbonate (CaCO3) and Hydrochloric Acid (HCl) are required for the preparation
of Carbon Dioxide.

Q.41. What is Dry Ice?
Ans. Solid Carbon Dioxide is called "Dry Ice".

Q.42. Why should the lower end of the thistle funnel be immersed in the liquid?
Ans. If the lower end of the thistle funnel is not immersed in the liquid the gas will
escape through the thistle funnel and will not be collected in the gas jar.

Q.43. Which substance is obtained if Carbon Dioxide is dissolved in water?
Ans. Carbonic Acid (H2CO3) is obtained when Carbon Dioxide is dissolved in water.

Q.44. Why does the milkiness disappear when Carbon Dioxide is passed through lime water
is excess?
Ans. The milkiness disappears due to formation of soluble Calcium Bicarbonate.

Q.45. Is Carbon Dioxide an element or a Compound?
Ans. Carbon Dioxide is a Compound of Carbon and Oxygen and its formula is CO2.

Q.46. Can any other compound be used instead of CaCO2?
Ans. Yes we can use any other metallic carbonate e.g. Na2CO3. It is due to the fact that HCl
reacts with metallic carbonates and decomposes them into respective chlorides and Carbon
Dioxide.

Q.47. Show the reaction of HCl on Marble Chips?
Ans. CaCO3 + 2HCl --------> CaCl2 + H2O + CO2.

Q.48. If we bring a burning match stick near the mouth of the gas jar then it gets
extinguished. Which property of Carbon Dioxide is displayed by this fact.
Ans. Carbon Dioxide is not a supporter of Combustion.

Q.49. Generally Carbon Dioxide is non supporter of combustion but burning magnesium wire
continues to burn. Why is it so?
Ans. It is due to the reason that heat produced by burning magnesium wire decomposes CO2
into Carbon and Oxygen and the Oxygen obtained helps it in burning brilliantly.
Q.50. Which are other metals which continue burning in it?
Ans. Highly reactive metals like Sodium, Potassium continue to burning in it.

Q.51. Write down the formulae of the following. Slaked LIme, Milk of Lime, Lime water.
Ans. All these substances have got the same formula Ca(OH)2.

Q.52. What is the nature of the gas?
Ans. It is acidic in nature and turns moist blue litmus red.

Q.53. What is the action of quick lime on Carbon Dioxide?
Ans. Quick Lime is converted to CaCO3.

Q.54. Why is it not collected by downward displacement of water?
Ans. It is soluble in water.

Q.55. What is the formula of Slaked Lime?
Ans. Ca(OH)2.

Q.56. What happens if quick lime is exposed to air?
Ans. It absorbs CO2 from air and changes into CaCO3.

Q.57. What is the formula of Carbonic Acid?
Ans. H2CO3.

Q.58. What is the formula of Lime Water?
Ans. Ca(OH)2.

Q.59. What is the difference between Slaked Lime and Lime Water?
Ans. Slaked Lime is in powdered state and when if slightly dissolves in water forms lime
water.

Q.60. What is left behind in Woulffe's Bottle after preparing this gas?
Ans. Calcium Chloride and Water.

Q.61. Why is it called Acid Gas?
Ans. It is called Acid Gas because it turns blue litmus red and it is sour in taste.

Q.62. Why Co2 is used in aerated Water?
Ans. It is used in aerated water because it helps in digestion and provides taste.

Q.63. Why do we keep the thistle funnel dipped in the liquid?
Ans. The thistle funnel is kept dipped in liquid so that the gas may not escape.

Q.64. What happens when a small animal is placed in Carbon Dioxide Jar?
Ans. It dies due to suffocation but it is not poisonous.

Q.65. How can you prove that the apparatus is air tight?
Ans. We can prove it by blowing air from the outer end of the delivery tube. If water rises
in the thistle funnel then it is air tight.



EXPERIMENT NO. 8



Viva Voce
Q.1. What is the formula of Hydrogen Peroxide?
Ans. The formula of Hydrogen Peroxide is H2O2.

Q.2. Is Hydrogen Peroxide an element or Compound?
Ans. Hydrogen Peroxide is a compound.

Q.3. How many elements are present in Hydrogen Peroxide?
Ans. Two elements.

Q.4. Write down the name of the elements present in Hydrogen Peroxide.
Ans. Hydrogen and Oxygen

Q.5. How many atoms of Hydrogen are present in Hydrogen Peroxide?
Ans. Two atoms of Hydrogen are present.

Q.6. How many atoms of Oxygen are present in Hydrogen Peroxide?
Ans. Two atoms of Oxygen are present in Hydrogen Peroxide.

Q.7. How do you make the apparatus air tight?
Ans. The apparatus is made air tight with the help of Plaster of Paris.

Q.8. What is the formula of Plaster of Paris.
Ans. The formula of Plaster of Paris is 2CaSO4.H2O.

Q.9. What is the formula of Manganese Dioxide?
Ans. The formula of Manganese Dioxide is MnO2.

Q.10. Which elements are present in Manganese Dioxide?
Ans. Manganese and Oxygen are present.

Q.11. How many atoms of Oxygen are present in Manganese Dioxide?
Ans. Two atoms of Oxygen are present in Manganese Dioxide.

Q.12. Write down the Chemical equation of Oxygen preparation reaction.
Ans. 2H2O2 + MnO2 ------- MnO2 + 2H2O + O2.

Q.13 Why do you add up MnO2 with Hydrogen Peroxide?
Ans. Manganese Dioxide is used in this reaction as Catalyst.

Q.14. Is Oxygen an element or Compound?
Ans. Oxygen is an element.

Q.15. What is Catalyst (Catalytic Agent)?
Ans. The substance which changes the rate of Chemical reaction without itself undergoing
permanent chemical change is called Catalyst.

Q.16. What is the function of Manganese Dioxide in the experiment?
Ans. The use of Manganese Dioxide increases the speed of Chemical reaction.

Q.17. What do you understand by Positive or Negative Catalyst?
Ans. Positive Catalyst The Catalyst which increases the rate of chemical reaction is
called Positve Catalyst.
Negative Catalyst The Catalyst which reduces the rate of reaction is called Negative
Catalyst.

Q.18. Give some examples of Negative Catalyst?
Ans. The addition of Acetanilide reduces the decomposition of Hydrogen Peroxide into water
and Oxygen.

Q.19. Give some example of Positive Catalyst?
Ans. Oxides of Iron, Potassium and Aluminium and Manganese are used as Positive Catalyst.

Q.20 By which method oxygen is collected?
Ans. Oxygen is collected by downward displacement of water.

Q.21. Can we collect Carbon Dioxide also by downward displacement of water?
Ans. No, Carbon Dioxide can not be collected by this method because it is highly soluble in
water.

Q.22. Is Oxygen heavier or lighter than air?
Ans. Oxygen is slightly heavier than air.

Q.23. Why is it advised to keep the lower end of thistle funnel dipped in the liquid?
Ans. The lower end of thistle funnel should remain dipped so that the gas may not escape
through the thistle funnel.

Q.24. What is the colour of the Gas?
Ans. It is colourless.

Q.25. What is the odour (smell) of the Gas?
Ans. It is odourless.

Q.26. Is it soluble in water?
Ans. It is slightly soluble in water.

Q.27. What happens when burning match stick is introduced into oxygen gas jar?
Ans. The match stick burns more readily.

Q.28. What do you conclude from the fact that the burning match stick burns more readily
in oxygen?
Ans. We conclude that oxygen is supporter of combustion.

Q.29. What happens when burning magnesium wire is introduced into gas jar?
Ans. Mangesium wire continues burning producing Magnesium Oxide.
2Mg(s) + O2(g) --2MgO(s)

Q.30. What happen if burning Sulphur powder is introduced into oxygen gas jar?
Ans. Sulphur continues burning producing Sulphur Dioxide
S(s) + O2(g) ---- SO2(g)

Q.31. What happens if burning sodium piece is introduced into gas jar?
Ans. Sodium continues burning producing Sodium Peroxide.
2Na(s) + O2(g) (Excess) -----> Na2O2

Q.32. What happens when a piece of burning Phosphorus is introduced into gas jar?
Ans. Phosphorus burns in oxygen forming phosphorus Pentaoxide.
4P(s) + 5 O2(g) -----> 2P2O5

Q.33. Give four uses of Oxygen?
Ans.
1. Oxygen is most essential for all living bodies, both animals and plants. Oxygen is used
in hospitals for artificial respiration.
2. It is used for converting Pig iron into steel in the blast furnance.
3. Acetyline is mixed with oxygen for producing a temperature as high as 3000oC which is
used for welding and cutting materials.
4. Liquid Oxygen is used as burning fuel in space.

Q.34. What is the name of binary compound formed with Oxygen?
Ans. The binary compound with oxygen is called Oxide.

Q.35. How many kinds of oxides are there?
Ans. There are four kinds of oxides
1. Normal Oxides
2. Peroxides
3. Superoxides
4. Suboxides.

Q.36. What are Peroxides?
Ans. Peroxides are binary compounds containing two oxygen atoms linked together.

Q.37. What happens when peroxides are treated with water?
Ans. Peroxides produce Hydrogen Peroxides when treated with water.
Na2O2 + 2H2O ------> 2NaOH + H2O2

Q.38. What is the name of that chemical process in which oxygen combines with other elements?
Ans. It is known as Oxidation.

Q.39. Does catalyst change the end of chemical reation?
Ans. No, Catalyst does not change at the end of Chemical reactions.

Q.40. What is Catalyst?
Ans. The process by virtue of which a catalyst, changes the rate of reaction is called Catalyst.
Q.41. What are Promoters?
Ans. The substances which enhance the activity of a catalyst are known as Promoters.

Q.42. What are Catalytic Poisons?
Ans. The substance which reduce or spoil the activity of a Catalyst are called Catalytic Poisons.

Q.43. What is Homogeneous Catalysis?
Ans. If the Catalyst, Reactants and Products all are in one phase, then such Catalyst is called Homogeneous Catalysis.

Q.44. What are the precautions in this experiment?
Ans. The following precautions should be taken in this experiment.
1. The round bottom flask should be air tight.
2. Round bottom flask should be heated gently by the tip of the flame.
3. The lower end of the thistle funnel should be immersed in the liquid.



EXPERIMENT NO. 9


Viva Voce
Q.1. What is the formula of Ammonia?
Ans. NH3.

Q.2. Wha is the formula of Ammonium Chloride?
Ans. NH4cl.

Q.3. What is the formula of Quick Lime?
Ans. CaO.

Q.4. What is the chemical name of Quick Lime?
Ans. Calcium Oxide.

Q.5. What do you mean Sal Ammoniac?
Ans. Ammounium Chloride is also known as Sal Ammoniac.

Q.6. What is the molecular weight of Ammonia (NH3)?
Ans. The molecular weigth of Ammonia is 17.

Q.7. How will you prepare Ammonia in Science Laboratory?
Ans. Ammonia is prepared in the Laboratory by heating a mixture of Ammonium Chloride and
powdered quick lime (CaO) or Slaked lime Ca(OH)2.

Q.8. Write down the chemical equation concerning the preparation of Ammonia?
Ans.
2NH4cl + CaO --------> 2 NH3 + CaCl2 + H2O
2NH4Cl + Ca(OH)2 ----> 2NH3 + CaCl2 + 2H2O

Q.9. What are the other compounds which are formed besides Ammonia during chemical action
of Ammonium Chloride with Quick Lime or Slaked Lime?
Ans. The other components which are formed besides Ammonia are Calcium Chloride.

Q.10. Which ratio Ammonium Chloride and Dry Slaked lime are taken.
Ans. NH4Cl = 1 Part, Slaken Lime = 2 Parts i.e. 1:2

Q.11. How is Ammonia collected?
Ans. Ammonia is collected by upward displacement of Gas.

Q.12. It is lighter or heavier than air?
Ans. It is lighter than air.

Q.13. Do you heat the mixture of Ammonium Chloride and Slaked Lime?
Ans. Yes, heating is required.

Q.14. Do you collect the gas over water?
Ans. No, it can not be collected over water because it is soluble in water.

Q.15. How will you know that the jar is full with the gas?
Ans. A rod dipped in Hydrochloric Acid when brought near its mouth gives white fumes of
Ammonium Chloride. A moist red litmus paper brought near the mouth will turn blue.

Q.16. Why is it essential to take perfectly dry gas jars for the collection of gas?
Ans. Ammonia is highly soluble in water.

Q.17. How will you keep the Gas Jars on the table afte they have been filled with the
gas?
Ans. The Jars will be kept in the inverted position because the gas is lighter than air so
in this case there is less chance for the leakage of the gas.

Q.18. What precautions are observed in this case?
Ans.
1. Gas Jars should be perfectly dry.
2. The Gas Jar is placed in inverted position with the help of a stand for collecting the
gas.
3. Gas is collected by downward displacement of air.
4. The Jars should be placed in inverted position after they have been filled with the Gas.

Q.19. Can you take quick lime for preparing the gas?
Ans. Yes, we can take quick lime also for preparing the gas.

Q.20. What is the colour of Ammonia?
Ans. It is colourless.

Q.21. What is the smell of Ammonia?
Ans. It has pungent smell.

Q.22. What is the taste of Ammonia?
Ans. It has bitter taste.

Q.23. It is soluble in water?
Ans. It is highly soluble in water.
Q.24. It is heavier than air?
Ans. No, it is lighter than air

Q.25. What is the action of Ammonia on Hydrochloric Acid?
Ans. Ammonium chloride is formed.

Q.26. Why does Ammonia give white fumes with conc.HCl.
Ans. Ammonia Gas and Hydrochloric Acid combine chemically to form Ammonium Chloride. But
Ammonium chloride is sublime substance so due to sublimation it directly changes into solid
from gaseous state. Due to this fact white fumes are visible.

Q.27. What is meant by "Downward Displacement of Air"?
Ans. When a gas is collected during preparation by keeping the jar in inverted position then
denser air is displaced downward. Therefore this is method is called "Downward Displacement
of Air".

Q.28. What is the action of Ammonia on Phenolphtalene?
Ans. Phenolphtalene solution become pink showing that Ammonia has basic character.

Q.29. How can Ammonia Gas be dried during experiment?
Ans. Ammonia Gas can be dried by passing it through a U-tube containly Quick lime.

Q.30. What is Nessler's Reagent?
Ans. Potassium Mercury Iodide is called NESSLER'S Reagent. It is a obtained by the following
chemical action.
Hgl2 + 2Kl --------> k2(Hgl4)

Q.31. Why do you collect Ammonia by downward displacement of gas?
Ans.Ammonia gas in lighter than air so it is collected by downward displacement of gas.

Q.32. State whether Ammonia is an element or a compound?
Ans. Ammonia is a compound of Nitrogen and Hydrogen.

Q.33. Is it a Basic or Acidic Gas?
Ans. It is a Basic Gas and turns red litmus blue.

Q.34. What is Chemical name of Nessler's Reagent?
Ans. The Chemical name of Nessler's Reagent is Potassium Mercuric Iodide and its formula is
K2(Hgl4)

Q.35. What substance is obtained when Ammonia is dissolved in water?
Ans. Ammonium Hydroxide is formed
NH3 + H2O ----- NH4OH

Q.36. What happens when Ammonia is treated with Copper SUlphate solution?
Ans. If Ammonia is treated with Copper sulphate solution then blue solution of complex Tetra
Amine Cupric Sulphate is formed
CuSo4 + 4 NH3 ------> Cu (NH)4 SO4 / Tetra Amine Cupric Sulphate

Q.37. What are some important uses of Ammonia?
Ans.
1. It is used in Ice making and Refrigeration.
2. It is used in making washing soda.
3. Ammonia solution (NH4OH) is used in laboratory as reagent.

Q.38. How Nessler's reagent is prepared?
Ans. Nessler's Reagent is prepared by adding excess of Potassium Iodide (Kl) solution into
the solution of Mercuric Chloride (HgCl2). Then Potassium Hydroxide is added to make the
Solution Alkaline.

Q.39. How will you identify Ammonia Gas?
Ans.
1. It possess a peculiar type of pungent smell and turns red litmus blue.
2. It gives white fumes with HCl.

Q.40. What is the difference between NH3 and NH4?
Ans. NH3 represents a molecule of Ammonia gas and NH4 stands for Ammonium Radical.

Q.41. What is the action of Ammonia on water?
Ans. Ammonia dissolves in water an forms Ammonium Chloride.
NH3 + H2O -------> NH4OH

Q.42. Why is it advised not to collect Ammonia in wet jar?
Ans. Ammonia is highly solube so it dissolves in the water of the wet jar and forms Ammonium
Hydroxide. Hence no gas is left in the jar.

Q.43. What is the nature of the gas?
Ans. It is basic in nature and turns moist red litmus blue.

Q.44. What are some of its physical properties which you observe during its preparation
and collection.
Ans. It is colourless with pungent smell and it is lighter than air and highly soluble in
water.

Q.45. Does it support combustion?
Ans. No, it does not support combustion.

Q.46. Does it burn in air?
Ans. No, it does not burn in air.

Q.47. What is the action of Turmeric paper on Ammonia?
Ans. Turmeric paper turns brown.

Q.48. Why does it turn turmeric paper brown?
Ans. It has property of base.

Q.49. What is Ionic Equation for the preparation of Ammonia?
Ans. (Ca++ + 2OH-) + 2(NH++4 + Cl-) -------> (Ca++ + 2Cl-) + 2H2O + 2NH3

Q.50. What does it show when the red litmus is turned blue by the action of Ammonia?
Ans. It shows that Ammonia has the property ofa base.

Q.51. What are the main tests of this gas?
Ans.
1. It has a pungent smell.
2. It turns red litmus blue.
3. It gives white fumes of Ammonium Chloride with HCl.

Q.52. What is the formula of Liquor Ammonia?
Ans. NH4OH.
Q.53. How will you demonstrate the solubility of Ammonia?
Ans. Its solubility is demonstrated by Fountain's Experiment.

Q.54. What do you understand by Liquor Ammonia?
Ans. Strogest solution of gas in water is called Liquor Ammonia and when the solution is
boiled Ammonia is give out.

Q.55. What is taste of Ammonia?
Ans. Alkaline or bitter taste.

Q.56. Does Ammonia support combustion?
Ans. No it does not support combustion.

Q.57. What do you understand by Spirit of Hartshorns?
Ans. Solution of Ammonia in water i.e. NH4OH is called Spirit of Hartshorns.

Q.58. What happens when a lighted candle is introduced in the gas jar full of Ammonia?
Ans. Candle gets extinguished which proves that Ammonia does not support combustion.

Q.59. How will you prepare Nessler's Reagent?
Ans. Potassium Iodide solution is added slowly in Mercuric Chloride solution till the red
precipitate formed dissolves in it and then add KOH solution till it is alkaline. It is then
Nessler's Reagent.

Q.60. What happen when Dry Ammonia is treated with Red Litmus paper?
Ans. No Reaction.

Q.61. What happen if you keep empty jar over Ammonia gas jar?
Ans. Gradually Ammonia gas diffuses into the upper Gas jar.



EXPERIMENT NO. 10


Viva Voce
Q.1. Who discovered Hcl Gas?
Ans. It was discovered in 1664 for the first time by Basll Valentine.

Q.2. Who prepared it first?
Ans. Joseph Priestly prepared it in 1772 and collected over Mercury and he called it Marine Acid air. It was prepared from Sea Salt.

Q.3. What is the reaction of Hydrogen and Chlorine?
Ans. If equal volumes of gases are taken and mixed together in bright sunshine then the gases combine together with great explosion.

Q.4. How will you prepare Hydrochloric Acid gas in Science Laboratory?
Ans. It is prepared in the Science Laboratory by the action of sulphuric Acid on Sodium Chloride
NaCl + H2SO4 -------> NaHSO4 + HCl (Low Temperature)
2 NaCl + H2SO4 -----> Na2SO4 + 2HCl (High Temperature)

Q.5. Can you use Nitric Acid (HNO3) or Hydrochloric Acid in place of SUlphuric Acid (H2SO4) for preparing Hcl gas?
Ans. No.

Q.6. Give the name of Apparatus used in this experiment?
Ans.
1. Gas Jar
2. Flask
3. Wire Gauze
4. Tripod Stand
5. Spirit Lamp
6. Delivery Tube
7. Thustle Funnel

Q.7. In what position Thistle Funnel should be placed?
Ans. It should be passed through the hole of the cork vertically and should reach the bottom and he dipped in Acid.

Q.8. Why should the thistle funnel be dipped in Acid?
Ans. In this way there is no escape of HCl gas from the flask

Q.9. At what angle should the delivery tube be placed?
Ans. It should be bent twice at Right Angle.

Q.10. How will you collect this gas?
Ans. It is heavier than air so it is collected by upward displacement of air.

Q.11. Why is it advised to take dry gas jars?
Ans. The Gas is soluble in water.

Q.12 What are the main precautions in this experiment?
Ans.
1. The apparatus should be air tight.
2. The Gas jar should be dry.
3. The thistle funnel should remain dipped into the acid.
4. The gas is collected by upward displacement of air.
5. The Gas jar after they are full should be placed with their mouth upward.

Q.13. What do you understand by Halogens?
Ans. Fluorine, Chlorine, Bromine. Iodine, Astatine together form a remarkable family of element. The whole group is called the Halogen. Halogen means Solt Producer.

Q.14. What are Halides?
Ans. The chlorides, fluorides, Bromides and Iodides are called Halides.

Q.15. What do you understand by Aqua Regia?
Ans. Three parts of conc Hcl and one part of Conc. HNO3 is known as Aqua Regia (Royal Water) because Gold dissolves in it and Arabian Chemist knew it in 8th century.

Q.16. Why do you call tids gas as Hydrogen Chloride?
Ans. The gas is composed of Hydrogen and Chlorine and so it is alos known as Hydrogen Chloride.

Q.17. How do you prepare Hydrochloric Acid from Hydrogen Chloride Gas?
Ans. Hydrochloric Acid Gas is extremely soluble in water so when it is passed through water forms Hydrochloric Acid.

Q.18. What happens when Silver Nitrate solution is treated with Hydrochloric Acid gas dissolved in water?
Ans. A white precipitate of Silver Chloride is formed which is soluble in Ammonium Hydroxide.
AgNO3 + HCl ------> AgCl + HNO3

Q.19. What happen when a glass rod dipped in Ammonium Hydroxide in introduced in the jar of HCl gas?
Ans. White fumes are formed due to formation of Ammonium Chloride.
NH4OH + HCl ------> NH4Cl + H2O

Q.20. What happens when Hydrochloric Acid is treated with Sodium Hydroxide?
Ans. When Hydrochloric Acid is treated with Sodium Hydroxide then Neutralization takes place salt and water are formed.
HCl + NaOH ----> NaCl + H2O
Q.21. What is the colour of HCl gas?
Ans. It is a colourless gas.

Q.22. What is the smell of HCl gas?
Ans. It has pungent irritating smell.

Q.23. What is taste of HCl gas?
Ans. It has an acidic taste.

Q.24. What happens if a burning candle is introduced into HCl gas jar?
Ans. It gets extinguished and the gas does not burn.

Q.25. What is the action of moist blue litmus paper with HCl gas?
Ans. The blue litmus paper turns red indicating that HCl gas is acidic in nature.

Q.26. Is gas lighter or heavier than air?
Ans. The gas is heavier than air.

Q.27. Is the gas soluble in water?
Ans. The gas is soluble is highly soluble in water.

Q.28. What are the used of Hydrochloric Acid Gas?
Ans.
1. Hydrochloric Acid Gas is used in preparing Hydrochloric Acid.
2. Hydrochloric Acid is used in Electroplating.
3. It is used in textile, dye and drug industry.
4. Hydrochloric Acid is widely used as a common reagent.
5. It is also used for manufacture of Chlorine, Bleaching Powder and Aqua Regia.

Q.29. Does this gas support Combustion?
Ans. No, it does not support combustion.

Q.30. State whether the gas is an element or a compound?
Ans. The gas is compound.

Q.31. What substance is obtained if you dissolve HCl gas in water?
Ans. If Hydrochloric Acid gas is obtained in water then Hydrochloric Acid is obtained.

Q.32. What chemicals are required for preparing HCl gas in Science Laboratory?
Ans. Sodium Chloride (NaCl) and Sulphate Acid (H2SO4) are required in the preparation of Hydrogen Chloride gas.

Q.33. Why is the gas not collected in the wet gas jar?
Ans. The gas is not collected in the wet jar because it is soluble in water.

Q.34. By which method Hydrochloric Acid gas is collected?
Ans. It is collected by the upward displacement of air because it is heavier than air.

Q.35. What are the precautions in this experiment?
Ans.
1. All the apparatus should be air tight.
2. It should be prepared in a well ventilated room.
3. Small quantity of Chemicals should be taken in the round bottomed flask.
4. The gas is must be dry.
5. The lower end of the thistle funnel should be kept immensed in the acid.

Q.36. How do you confirm whether the jar is completely filled up with the gas or not?
Ans. If we bring a rod moistened with Ammonium Hydroxide near the mouth of the jar then the white fumes of Ammonium Chloride ar produced which indicates that the jar is full of HCl gas.

Q.37. Why a burning match stick is put off when introduced in the jar of this gas?
Ans. It is due to the reason that gas is not a supporter of combustion.

Q.38. What is the action of Hydrochloric Acid on the metals like Za, Na, K etc.
Ans. It reacts with many metals forming their chlorides and Hydrogen gas is given out.
Zn + 2HCl --------> Zin Cl2 + H2
2K + 2Hcl --------> 2KCl + H2
Q.39. What are the other methods of preparing HCl?
Ans.
1. By the direct combination of Hydrogen and Chlorine.
2. By the action of Chlorine on Hydrogen Compound.

Q.40. What is left behind in the flask after preparation of this gas in Science Laboratory?
Ans. Sodium Sulphate.

Q.41. How will you identify this gas?
Ans. It turns blue litmus red, forms white precipitate with Silver Nitrate.

Q.42. What are Acids?
Ans. Acids are those compounds which are sour in taste, turn blue litmus and give H+ ions in water.

Q.43. How would you prove that HCl gas is highly soluble in water?
Ans. It can be proved by performing fountain experiment.

Q.44. How do you prepare dilute acid from HCl, HNO3 and H2SO4?
Ans. We should never add water to the bottle of concentrated acid because when acid dissolves in water large quantity of heat is produced and it also dissolves violently so the bottle may break. Hence in order to prepare dilute acid we must pour Conc. acid slowly into vessel containing water, but we must never pour water in Conc. acid.

Q.45. Why is it called HCl?
Ans. It is a compound of Hydrogen and Chlorine?

Q46. What substance is obtained when the gas is dissolved in water?
Ans. Hydrochloric Acid is formed.

Q.47. How will you maintain the regular flow of the gas?
Ans. By warming the flask gently towards the end the regular supply of the gas is maintained.

Q.48. Can you collect this gas over water like Hydrogen and Oxygen gas?
Ans. No, it can not be collected because it is highly soluble in water.
Q.49. How will you know with the help of Litmus paper that the jar is of gas?
Ans. If we bring a moist blue litmus paper near the mouth of gas jar, it turns red.

Q.50. How do you prepare HCl on large scale?
Ans. It is generally prepared on large scale by the reaction of common salt and conc. H2SO4.

Q.51. Why is it so that the colour of commercial Hydrochloric Acid is yellow?
Ans. Due to presence of Ferric Chloride (FeCl3) the colour is yellow.

Q.52. How many times it is heavier than Hydrogen?
Ans. It is 18.25 times heavier than Hydrogen.

Q.53. Does it burn in air?
Ans. No it does not burn in air.

Q.54. Can it be liquified?
Ans. Yes, it can be liquified to a colourless liquid.

Q.55. What is Fountain's Experiment?
Ans. Take a dry flask fitted with rubber stopper and a glass tube ending in a flask. Fill the flask completely with HCl gas. Now dip the other end into water containing blue litmus solution. After some time water rushes up in the form of fountain in the flask and its colour changes from blue to red.

Q.56. What is the action of dry HCl gas on dry blue litmus?
Ans. Dry HCl gas has no action on dry blue litmus paper.

Q.57. What happen if the glass cover of HCl gas jar is removed?
Ans. If the glass cover is removed from the mouth of a jar it fumes in contact with moist air.

Q.58. What are the main important tests of HCl gas?
Ans.
1. HCl gas forms with Ammonia white fumes of NH4Cl (Ammonium Chloride).
2. If HCl is passed through test tube containing MnO2 then Chlorine is evolved.
3. Solution of HCl gas in water turns.
4. Gives a white precipitate of AgCl with AgNO3 solution.



EXPERIMENT NO. 11


Electrolytes Sodium Chloride solution Acidified water caustic soda solution.
Non-Electrolytes Sugar solution, Benzene, Alcohal.

Q.1. Which materials are required in Electroplating experiment?
Ans. The following materials are required in electroplating experiment.

Q.2. Which materials are required in experiment 11(B)?
Ans. The following material is required in experiment 11 (B):
1. Battery
2. Beaker
3. Electrodes
4. Bulb or Galvanometer and connecting wire

Q.3. What is electrolytes?
Ans. The movement of the ions of an electrolyte and their deposition as neutral species at
the electrodes under the influence of electric current is known as Electrolytes..
Q.4. What are the conditions for Electrolysis?
Ans. The electrolytes should be in the form of solution of strong electrolyte. It may also
dissociate in molten or fused state. If the solution is more dilute and the temperature is
higher then the degree of dissociation is greater.

Q.5. What is the name of metallic plates which are placed in the electrolyte?
Ans. The metallic plates are called electrodes.

Q.6. What is the name of the plate connected to positive terminal of the battery?
Ans. It is known as Anode.

Q.7. What is the name of electrode connected to negative terminal of the battery?
Ans. That electrode is called Cathode.

Q.8. Which compound is used as electrolyte in this experiment?
Ans. Copper Sulphate is used as electrolyte in this experiment.
Q.9. To which terminal of the battery the iron strip should be connected?
Ans. Iron strip for electroplating with copper should be connected to negative plate of the
battery.

Q.10. Why do you connect Iron plate to negative plate of the battery?
Ans. As we want to coat Iron plate with copper so it is made negative so that positive
copper ions may deposit on iron strip.

Q.11. What are Electrolytes?
Ans. Electrolytes are the substance which in fused state or in aqueous solution dissociate
into ions and conduct electricity.

Q.12. What are Non-Electrolytes?
Ans. Non-Electrolytes are those substances which in fused state or in aqueous solution do
not dissociate into ions and hence do not conduct electricity.

Q.13. Give some examples of Electrolytes?
Ans. Acids, Bases and Salts are the examples of Electrolytes.

Q.14. Give some examples of Non-Electrolytes?
Ans. Alcohal, Benzene, Sugar Solution, Carbon Disulphate and Carbon Tetrachloride are the
examples of Non-Electrolytes.

Q.15. What is Electroplating?
Ans. Electroplating is a process in which a thin layer of a metal is coated on the other
metal with the help of electric current.

Q.16. What is the purpose of Electroplating?
Ans. The purpose of electroplating is to make the metallic plate shining and durable.

Q.17. Which compounds are Electrolytes and Non-Electrolytes in the following compound?
Ans.
1. Potassium Chloride Solution
2. Sodium Hydroxide Solution
3. Sugar Solution
4. Benzene
5. Hydrochloric Acid
6. Potassium Hydroxide
7. Alcoha

Q.18. What is the formula of Copper Sulphate?
Ans. The formula of Copper Sulphate is CuSO4.5H2O

Q.19. Which chemicals are used in Dry Cell?
Ans. The chemicals which are used in Dry Cell are given below:
1. Ammonium Chloride
2. Zinc Chloride
3. Manganese Dioxide
4. Charcoal

Q.20. Which substance is used as negative electrode in Dry Cell?
Ans. Zinc vessel is used in negative electrode.

Q.21. Which substance is used as positive electrode in Dry Cell?
Ans. Carbon Electrode is used as positive electrode in Dry Cell.

Q.22. Which compound is used as electrolyte in Dry Cell
Ans. Ammonium Chloride solution is used as an electrolyte in Dry Cell.

Q.23. Which chemical compound is used as electrolyte in simple Voltaic Cell?
Ans. Dilute Sulphuric Acid is used as electrolyte.

Q.24. Which substance is used as positive electrode in Voltaic Cell?
Ans. Copper Plate is used as Positive electrode.

Q.25. What are Faraday's Laws of Electrolysis?
Ans. Faraday's Laws of Electrolysis are given below:
First Law The amound of electrolysis which takes place is in exact proportion to the
quantity of electricity which is used in the process.
Second Law Mass of any substance formed by the passage of given amount of electricity
is directly proportional to the equivalent weight of the solution.

Q.26. What is the unit of Charge?
Ans. The unit of Charge is coulomb.

Q.27. Define Coulomb?
Ans. One coulumb is defined as the quantity of electrocity which will deposit 0.00 11180 g
of silver from a solution of Silver Nitrate.

Q.28. What is the unit of Current?
Ans. The unit of current is ampere.

Q.29. What is Ampere?
Ans. A current of one ampere corresponds to the transfer of electricity at a rate of 1
coulomb per second.

Q.30. Define Volt?
Ans. A Volt is the potential difference across the two ends of a wire of one ohm resistance
and in which one ampere current is flowing.

Q.31. Which substance is used as negative electrode in simple Voltaic Cell?
Ans. Zinc plate is used as negative plate in this Cell.

Q.32. Why does the current stop in voltaic cell after some time?
Ans. The current stops after some time due to defect of Polarisation.

Q.33. What is Polarisation?
Ans. Depositing of hydrogen gas on copper plate is known as Polarisation.

Q.34. What is the formula of Sodium Chloride?
Ans. The formula of Sodium Chloride is NaCl.

Q.35. What is the formula of Sodium Hydroxide?
Ans. NaOH.

Q.36. What is the formula of Sugar?
Ans. C12H22O11.

Q.37. What is the formula of Methyl Alcohal?
Ans. CH3OH

Q.38. What is the formula of Ethyl Alcohal?
Ans. C2H5 OH.

'Q.39. What is the formula of Glucose?
Ans. C6H12O6.

Q.40 Is Alcohal an electrolyte?
Ans. No, alcohal is not a electrolyte.

Q.41. What is the formula of Benzene?
Ans. C6H6.

Q.42. Is Benzen an aliphatic or aromatic compound?
Ans. Benzene is an aromatic compound.

Q.43. Why does the current flow through Electrolytes?
Ans. Electrolytes in the form of solution contain positive and negative ions. The ions are
charged particles so they help in the flow of electric current through them.

Q.44. Why does the current not flow through non-electrolytes?
Ans. Non-electrolytes do not break into ions and so they do not allow the flow of electric
current through them.
Q.45. What is an Ion?
Ans. An atom or group of atoms having positive or negative charge is known as Ion.

Q.46. What is Cation?
Ans. Ion Carrying positive charge is called Cation.

Q.47. What is Anion?
Ans. Ion carrying negative charge is called Anion.

Q.48. What are the Strong Electrolytes?
Ans. The compounds which ionize to a large extent in dilute aqueous solutions and therefore conduct electric current to a large extent are called Strong Electrolytes.

Q.49. Give some examples of Strong Electrolytes?
Ans. HCl, NaOH, H2SO4, NaCl are the examples of Strong Electrolytes.

Q.50. What do you understand by Weak Electrolytes?
Ans. The compounds which conduct electric current poorly due to ionization to a small extent in aqueous solutions are called Weak Electrolytes.

Q.51. Give some examples of Weak Electrolytes?
Ans. Acetic Acid, Sodium Carbonate and Calcium Hydroxide are the examples of Weak Electrolytes.

Q.52. Define Faraday?
Ans. The number of coulomb required to liberate 1.008 g of Hydrogen or deposit 31.78 g. of copper is equal to 96500 coulomb. This amount of charge is called a Faraday.



EXPERIMENT NO. 12


Q.1. What is an Ion?
Ans. When an electrolyte dissolves in water then it breaks into positive and negative parts known as Ion.

Q.2. What is Cation?
Ans. The positive Ion is called as Cation.

Q.3. What is Anion?
Ans. The negative ion is called Anion.

Q.4. Explain clearly what do you understand by Ion?
Ans. Ion is an atom or a collection of atoms which are positively or negatively charged.

Q.5. What happens when a salt is dissolved in water?
Ans. A salt when dissolved in water breaks into ions.

Q.6. What is the colour of Chlorine Vapours?
Ans. Greenish Yellow.

Q.7. What is the colour of Bromine Vapours?
Ans. Brown.

Q.8. What is the colour of Iodine Vapours?
Ans. Violet.

Q.9. On addition of Manganese Dioxide and conc H2SO4 to the salt, if greenish yellow gas is given out then what do you suspect?
Ans. Chlorine Gas.

Q.10. Give an equation to explain the reaction of MnO2, H2SO4(conc) and the salt?
Ans. 2NaCl + MnO2 + 2H2SO4 ------> MnSO4 + Na2SO4 + 2H2O + Cl2

Q.11. What happens when Silver Nitrate (AgNO3) solution is added to the solution of Chlorine Salt.

Ans. It gives white precipitate of Silver Chloride.
AgNO3 + NaCl ------> AgCl + NaNO3
Q.12. What happen if we added Ammonium Hydroxide (NH4OH) to the test tube containing Silver Chloride precipitate?
Ans. Precipitate disappears.
AgCl + 2NH4OH -------> [Ag(NH3)2] Cl + H2O (Complex Diamine Chloride)

Q.13. Why do you use concentrated H2SO4?
Ans. Concentrated Sulphuric Acid helps us in displacing these ions in the form of Vapours.

Q.14. What happen if we add cold H2SO4 and salt to it?
Ans. At low temperature HCl is evolved and so we get colourless vapours of HCl, HBr and Hl, Hence these ions cannot be separated.

Q.15. Why is heating necassary after adding cone H2SO4?
Ans. On heating HCl, HBr and Hl are oxided by concentrated H2SO4 to brown vapours of Bromine and violet vapours of Iodine.

Q.16. Why do we get white fumes in the test of Cl ions with Ammonium Hydroxide?
Ans. It is due to formation of Ammonium Chloride.

Cl + NH4OH -------> NH4Cl + OH.

Q.17. Why do we add Chlorine in confirmatory test for Bromine and Iodine?
Ans. Chlorine water is used for displacing Bromine (Br) and Iondine (I) ions to Br2 and I2 respectively.

Q.18. What is the function of Chloroform or Carbon Tetrachloric in the confirmatory test for Br- and I-?
Ans. The function of Chloroform or Carbon Tetrachloride is to dissolve Br2 and I2 which are displaced by Chlorine water. The reddish brown and violet colours of the layers are because of dissolved Br2 and I2 in Carbon Tetrachloride.

Q.19. Why does Br ion give brown vapours when heated with concentrated H2SO4?
Ans. It first forms HBr which upon heating is oxidised to form brown vapours of Br2.

Q.20. Why does I ions give violet vapours when heated with Concentrated H2SO4?
Ans. It first form Hl, which upon heating is oxidised to form violet vapours of I2.

Q.21. What are the sources of errors and precautions in this experiment?
Ans.
1. Do not throw acid directly into sink. To destroy it pour it first into water in a breaker and then throw it into the sink.
2. The solution should be prepared in distilled water.
3. Tests tube should be thoroughly washed.
4. Small quantity of Chemicals should be taken in test tube while carrying out tests.
5. Add small quantity of Sulphuric Acid each time.
6. Heating of test containing acid should be done carefully.

Q.22. What is the reaction of Concentrated H2SO4 on Na Br at low temperature?
Ans. When Bromide is treated with Concentrated H2SO4 gives H Br and NaHSO4
Na Br + H2SO4 -------> NaHSO4 + H Br

Q.23. What happen when a Bromide and Concentrated H2SO4 are heated?
Ans. First of all sodium Bi Sulphate is formed which on heating gives Bromine Water and Sulphur Dioxide.

Q.24. What is the reaction of Conc. H2SO4 on NaCl at low temperature?
Ans. Sodium Hydroxide Sulphate and Hydrochloric Acid are formed.

Q.25. What happen when Potassium Iodide is treated with Conc. H2SO4?
Ans. Potassium Hydrogen Sulphate and Hydrogen Iodide are formed.

Q.26. What happen when Potassium Iodide is heated with Conc. H2SO4?
Ans. When Potassium Iodide is heated with Conc. H2SO4 then Iodine water and Sulphur Dioxide are produced:
Kl + H2SO4 -------> K HSO4 + Hl
2Hl + H2SO4 ------> I2 + 2H2O + SO2

Q.27. What happens when a salt is dissolved in water?
Ans. A salt on dissolving into water is dissociated into its ions.

Q.28. What do you understand by confirmatory test?
Ans. Confirmatory test is a test by which an ion can be confirmed.

Q.29. Define a Salt?
Ans. Salt is a product of neutralisation between an acid and a base.

Q.30. Give some names of salt used in our daily life.
Ans.
1. Sodium Chloride (NaCl) It is a common salt that we use in our meals.
2. Calcium Carbonate (CaCO3) It is marble and used in construction of buildings.
3. Magnesium Sulphate (MgSO4) It is used a Laxative.
4. Calcium Phosphate [Ca3(PO4)2] It is moist essential for our bones.

Q.31. What is the name given to the process in which salt after being dissolved in water gets converted into ions?
Ans. This process is called Ionisation.

Q.32. When does an atom become Cation?
Ans. Atom is neutral but when it loses electron the positive charge appears on it and then it becomes Cation.

Q.33. When does an atom become Anion?
Ans. If an atom gains an electron then negative charge appears on it and then it becomes Anion.

Q.34. What is a Precipitate?
Ans. If two solutions are mixed and chemical reaction takes place between then then a result of which an insoluble compound is formed. This insoluble compound is called Precipitate.

Q.35. What are Ionic Compounds?
Ans. Those compounds which are formed by the combinations of ions are called Ionic Compounds. They are formed by ionic bonds.

Q.36. What happens when ionic compounds are dissolved in water?
Ans. When Ionic compounds are dissolved in water they break into positive and negative ions.

Q.37. What is the function of Chlorine Water in layer test for identification of Bromine and Iodine.
Ans. Chlorine is more active Chemically than Bromine and Iodine. It displaces Bromine and Iodine from their salt and liberates them in free state.

Q.38. What is the function of Carbon Tetrachloride in layer test?
Ans. Carbon Tetrachloride is used as SOlvent in this test. Free Bromine and Iodine become soluble in it.

Q.39. What are Halogens and Halides?
Ans. The word Halogen has been derived from the word HALDS meaning sea salt. Chlorine, Bromine and Iodine which form salts like sea salts are called Halogens. Salts of these elements are called Halides.

Q.40. How will you test for Chloride?
Ans.
1. If we heat the mixture with Conc. H2SO4 colourless pungent gas (HCl) is evolved. If a gas rod dipped in NH4OH is brought near the mouth of the test tube white dense fumes are formed.
NaCl + H2SO4 --------> Na HSO4 + HCl
NH4OH + HCl ---------> NH4Cl + H2O (White Fumes)
2. On heating the mixture with Conc. H2SO4 and MnO2 a greenish yellow gas (Chlorine) is evolved.
2NaCl + MnO2 + 2H2SO4 -------> 2NaHSO4 + MnSO4 + H2O + Cl2

Q.41. Can we use HCl in the test of Chloride?
Ans. No, HCl itself contains chloride.

Q.42. How do you test for Bromide?
Ans. When the mixture containing Bromide is heated with Conc. H2SO4 heavy brown vapours of Bromine are evolved.
NaBr + H2SO4 -------> NaHSO4 + HBr
2HBr + H2SO4 -------> 2H2O + SO2 + Br.

Q.43. What is Confirmatory test for Bromide?
Ans. When a Bromide is heated with MnO2 and H2SO4 reddish brown vapours of Br (Bromide) are evolved.

Q.44. How do you test for Iodide?
Ans.
1. Heat the mixture with Conc. H2SO4 when violet vapours are evolved
NaI + H2SO4 --------> NaHSO4 + Hl
2Hl + H2SO4 --------> 2H2O + SO2 + I2
2. On adding a pinch of MnO2 to the above mixture more violet vapours are evolved.
2Nal + MnO2 + 3H2SO4 -------> 2NaHSO4 + MnSO4 + 2H2O + l2

Q.45. Can you see Silver Nitrate for the detection of Halibes?
Ans. Yes we can use Silver Nitrate for the detection of Halides but the following precautions must be observed:
1. Distilled water must be used throughout.
2. Nitric Acid free from Chloride must be used Ordinary Nitric Acid contains Chloride as impurity.
3. Test tube and breakers must be washed with distilled water.
Q.46. Why Ordinary water should not be used for the test of Chloride?
Ans. Ordinary water contains chloride as an impurity. It produces a white precipitate with AgNo3 solution even in the absence of Chloride in the mixture.

Q.47. How many members are there in Halogen group?
Ans. Five members Flourine, Chlorine, Bromine, Iodine and Astatine.

Q.48. To which group of Periodic Table the Halogen elements belong?
Ans. The Halogen elements belong to VII B group.

Q.49. Is Astatine a radio active element?
Ans. Yes.

Q.50. Is Astatine found in Large quantities?
Ans. No, it is found in very small quantity.

Q.51. Whether Halogens are Electropositive or Electronegative?
Ans. They are Electronegative.

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