Chemistry capsule

For more downloads, visit www.studyiq.in

Premier Coaching Institute For

SSC,-CGL, Railways, RBI, Bank PO

A-91, 2nd Floor, Near Style Shoes,

Lajpat Nagar , New Delhi – 110024

Mo. 9716523859 ,9716523857

- By Dr. Gaurav Garg (Faculty General Science)


MATTER & PURE SUBSTANCES

Brownian motion: the zig-zag movement of the small particles suspended in a

liquids (or gas) is called Brownian motion.

Solutions: homogenous mixture of solute (the substance to be dissolved in liquid)

in solvent e.g. mixture of petrol & oil. Here, Concentration of a Solution is the

amount of solute present in a given amount (mass or volume) of solution. It is

expressed as

Mass by mass percentage = (mass of solute/mass of solution) * 100

Mass by volume percentage = (mass of solute/volume of solution) * 100

Suspensions: heterogeneous mixture in which small particles of a solid are spread

throughout a liquid without dissolving in it eg. Chalk water mixture.

Colliods: Kind of solution in which the size of solute particles is intermediate

between those in true solutions and those in suspensions eg. Soap solution,

starch solution, milk, jelly, fog, mist, sponge etc.

Note that: the scattering of a beam of light by particles in a colloid or particles in

a fine suspension is called Tyndall Effect.

The Effect of temperature and pressure on the solubility of a substance:

1) The solubility of solids in liquids usually increases on increasing the

temperature and decreases on decreasing the temperature.

2) The solubility of solids in liquids remains unaffected by the changes in

pressure.

3) The solubility of gases in liquids usually decreases on increasing the

temperature and increases on decreasing the temperature.

4) The solubility of gases in liquids usually increases on increasing the pressure

and decreases on decreasing the pressure.

Separation of mixtures:

Of solids

a. Suitable Solvent : one constituent of a mixture is soluble in a particular

liquid solvent whereas the other constituent is insoluble.eg. a mixture

of sand and sugar can be separated using water as solvent.


b. Sublimation is done when one constituent is capable of changing from

solid to vapours on heating or from vapours to solid on cooling .e.g.

Camphor, Iodine, Ammonium Chloride, Napthalene & Anthracene.

c. Magnet is used to separate a mixture of iron fillings & sulphur powder.

Of a solid and a liquid

a. By filtration: the mixture of insoluble solid and liquid is poured into a

filter paper cone fixed in a funnel by using a glass rod as guide.

b. Centrifugation is the process of separating the suspended particles

from a liquid in which the mixture is rotated at a high speed to

centrifuge. It is commonly used for uranium enrichment, relying on the

slight mass difference between atoms of U238 and U235 in uranium

hexafluoride gas. This is faster than filtration.

c. Evaporation

d. Distillation

e. Purification by Crystallization: The process of cooling a hot,

concentrated solution of a substance to obtain its crystals.

f. Separation by Chromatography: It is a technique of separating two (or

more) dissolved solids which are present in a solution in very small

quantities. E.g. Black ink is a mixture of several coloured dyes which can

be separated by paper chromatography.

The paper is placed in a container with a shallow layer of solvent and sealed. As the solvent rises through the paper, it meets the sample mixture, which starts to travel up the paper with the solvent. This paper is made of cellulose, a polar substance, and the compounds within the mixture travel farther if they are non-polar.

http://en.wikipedia.org/wiki/Uranium_enrichment

http://en.wikipedia.org/wiki/Uranium_hexafluoride

http://en.wikipedia.org/wiki/Uranium_hexafluoride

http://en.wikipedia.org/wiki/Solvent

http://en.wikipedia.org/wiki/Cellulose

http://en.wikipedia.org/wiki/Chemical_polarity

http://en.wikipedia.org/wiki/Chemical_polarity


Of liquids

a. Separating Funnel : a mixture of 2 immiscible liquids (e. Water &

kerosene oil) can be separated by a separating funnel based on the

difference in their densities.

b. Fractional Distillation is used to obtain a variety of products from

crude oil (a mixture of hydrocarbons), based on the principle that

lower hydrocarbons boil at a lower temperature than higher ones.


ATOMS AND MOLECULES

Laws of Chemical Combination

a. Law of Conservation of Mass: This law states that mass can neither be

created nor destroyed in a chemical reaction. The total mass of the

products is the same as the total mass of reactants.

b. Law of constant proportions: This law was stated by Proust. It states

that a pure chemical compound always consists of the same elements

combined together in a fixed proportion by weight e.g H2O prepared

from any source contains H & O in the ratio of 1:8 by mass.

According to Dalton’s Atomic Energy

1. All matter is made of very tiny particles called atoms.

2. Atoms are indivisible particles, which cannot be created or destroyed in

chemical reaction.

3. Atoms of a given element are identical in mass & chemical properties.

(Ruled out after the discovery of isotopes).

4. Atoms of different elements have different mass & chemical properties.

(Ruled out after the discovery of isobars eg. Argon, Potassium and Calcium

have same atomic mass 40 but different atomic number 18, 19 & 20

respectively).

5. When elements react, their atoms combine in simple whole number ratio.

Atomic Mass = Mass of one atom of the element

1/12th part of the mass of one atom of carbon

Atomicity: the number of atoms constituting a molecule. E.g. oxygen is diatomic.

Mole Concept:

Mole is a link between mass of a molecules and the number of atoms in

that molecule.

A group of 6.022 X 1023 (avagadro number of) particles (atoms, molecules

or ions) of a substance is called the mole of that substance.

1 mole of atoms of an element = gram atomic mass of the element


e.g. for oxygen atom, gram atomic mass is 16 units. But for oxygen molecule (O2),

gram molecular mass = 2 X 16 = 32 units

Substance Symbol/formula

Mass of 1 mole 1 mole contains

1 mole of H atom H 1 g 6.022 X 1023 hydrogen atoms

1 mole of hydrogen molecule

H2 2 X 1 = 2g 6.022 X 1023 hydrogen molecules

1 mole of water H2O 2 + 16 = 18g 6.022 X 1023 water molecules

1 mole of Ammonia molecule

NH3 14 + 3 = 17g 6.022 X 1023 ammonia molecules

Note that : isotones are the one with same number of neutrons e.g. H, He (2 each).

Isosters are molecules/ions with same number of atoms e.g. N2O , C2O

Structure of Atom:

Atomic number = no. of protons = 6

Mass number = no. of protons + no. of neutrons = 12.

Valence Electrons = those located in the outermost shell which take part in chemical reaction. Here, 4.

However, Valency of elements is defined as combining capacity of an atom by gaining

or losing valence electrons to gain octate state. E.g. Chlorine, atomic number = 17,

Configuration is 2 8 7. It needs only 1 electron to complete octate => its valency is 1.

The maximum no. of electrons present in a shell is given by 2n2.


Chemical Bonding

IONIC OR ELECTROVALENT BOND: formed by complete transfer of one or

more electrons from valence shell of one atom to another. The ion losing

electron gains positive charge and is called cation. The one gaining electrons

(or negatively charged) is anion.

Condition for the formation of ionic bonds :

a. Low ionization energy – one of the two atoms forming the ionic bond must

have low ionization energy so that it can easily lose electron and can form

a cation.

b. High Electron Affinity - the other atom which is accepting electron should

high electron affinity so that the electron lost by the first atom is readily

accepted by the second atom.

c. Larger cation & smaller anion.

d. High lattice energy (energy given off when oppositely charged ions in the

gas phase come together to form a solid. and hydration energy (Heat

released when 1 mole of gaseous ions dissolve in sufficient water to give

an infinitely dilute solution).

Properties:

1. Soluble in polar solvent.

2. High melting point and boiling point.

3. Good conductor in aqueous solution.

4. Non-inflammable.

5. Non-volatile.


Ionisation Energy: The energy required to remove an electron from the

outermost orbit of an isolated gaseous atom in its ground state. Along a Period,

Li < Be > B < C < O < N < F

This pattern can be explained by the factors given below:

1. Larger the size of atom, lower will be the ionisation energy.

2. Nuclear Charge: greater the nuclear charge, greater will be attraction of the

nucleus for the valence electrons, so will be ionisation energy.

3. Screening or Shielding effect: Greater the number of shells between the

nucleus and the valence electrons, lesser will be ionisation energy e.g. Lower

ionisation of B than Be id due to presence of more screening effect.

4. Presence of sub-shells: IE also depends upon the type s,p,d or f electrons

which are to be removed. S-electrons are closer to the nucleus & more tightly

held hence ionisation energy decreases in that order.

5. Stability of Configuration: Completely filled and exactly half filled sub-shells

impart extra stability which result in the higher IE. (IE of Nitrogen is greater

than oxygen because Nitrogen has stable half filled 2P sub level)

COVALENT BOND: formed by mutual sharing of electrons between atoms.

Conditions: a. Smaller the size, higher the covalency. b. Electronegative element + Electronegative

element c. High ionisation energy & d. High electron affinity.

CO-ORDINATE COVALENT BOND: characterized by one-sided sharing of electrons.

One of the combining atoms contributes both the electrons that form a bond

between them. Other atom does not contribute any of its own electrons but

acquires stable configuration by sharing the pairs of electrons contributed by the

1st atom e.g. HNO3


Valence electron in oxygen = 6

In nitrogen = 5

In hydrogen = 1

Nitrogen has completed its octate by sharing 3 electrons with oxygen atoms but still contributes its 2 electrons through one-sided sharing to the third oxygen atom.

Properties of Elements Behaviour along PERIODS Behaviour along GROUPS

Atomic Size Decreases from left to right Increase from up to down

Ionisation Potential Increases from left to right Decreases down the group

Electronegativity Increases from left to right Decrease from up to down


CHEMICAL REACTION

Chemical Reaction is the process in which new substances with new properties are

formed. During a chemical reaction, atoms of 1 element do not change into atoms of

another element. Only a rearrangement of atoms takes place.

Rate of Reaction = Change in concentration of a reactant

Time taken for change

Factors affecting the rate of reaction:

1. Concentration of reactants.

2. Temperature.

3. Catalyst.

4. Presence of light affecting photochemical reactions.

5. Physical nature of reactants and

6. Chemical nature of the reaction.

Types of Reaction

a. Exothermic Reaction: chemical reaction in which heat is evolved.

C + O2 -> CO2 +heat

b. Endothermic Reaction: chemical reaction in which heat is absorbed.

CaCO3 + heat -> CaO + CO2

Note that all decomposition reactions are endothermic.

c. Combination: 2/more substances combine to form a new substance.

2Mg + O2 -> 2MgO

d. Decomposition: A compound splits into 2/more simpler substances.

CaCO3 -> CaO + CO2

e. Displacement: one element takes the place of another in a compound.

CuSO4 + Zn -> ZnSO4 + Cu

f. Double Displacement: those reactions in which 2 compounds react by an

exchange of ions to form 2 new compounds.

AgNO3 + NaCl -> AgCl + NaNO3

Silver replaces sodium in sodium chloride and sodium replaces silver in

silver nitrate forming silver chloride and sodium nitrate respectively).


g. Oxidation : reactions involving addition of oxygen and/or removal of hydrogen.

Reduction : reactions involving addition of hydrogen and/or removal of oxygen.

Oxidising agent is ferrite because it helps in oxidation of CO.

Reducing agent is CO because it absorbed oxygen from ferrite.

h. Disproportion Reaction: where only 1 substance gets oxidised as well as reduced.

Cl2 + H2O -> HCl + HOCl (redox reaction where Cl is oxidised as well as reduced)

i. Neutralisation reaction: acid reacts with base to form salt.

NaOH + HCl -> NaCl + H2O

CHEMICAL EQUILIBRIUM :

a. At Equilibrium, both the forward & the backward reactions proceed at the

same rate and hence, the equilibrium is dynamic in nature.

b. At Equilibrium, all macroscopic properties such as pressure, concentration,

density, colour etc. of the system become constant and remain unchanged

thereafter.

c. Chemical Equilibrium can be established only when none of the product is

allowed to escape out.

d. Chemical Equilibrium can be approached from either direction.

Ionic equilibria:

1. Chemical reactions also takes place in solution in which generally ions

participitate.

2. The substances which furnish ions are known as electrolytes which may be

acids, bases or salt.

3. The equilibrium is present between the unionized molecules of a particular

substance and the ions formed in the solution.

4. Equilibrium constant is related to the strength of electrolyte.


Ostwald dilution law for weak electrolytes:- It states that “at constant

temperature, the degree of dissociation for weak electrolytes is directly

proportional to square root of its dilution”.

Note:- This law is not for strong electrolytes because these are approximately

100% ionised at all dilutions and dilutions has no effect on their dissociation.

Applications of Ostwald Dilution Law:

a. In determine strength of weak acid or base.

b. In calculation of degree of dissociation.

c. In calculation of relative strength of acid or base.

d. In calculation of [H+] and pH of aqueous solution.

Ionic Product of Water: Water dissociates slightly to give hydrogen ion (H+) and

hydroxide ions (OH-). This is a reversible reaction in which most of the water

remains in the undissociated molecular form (H2O) at the equilibrium state.

ACIDS & BASES

Acids Bases 1. Tastes sour Tastes bitter, soapy in touch 2. Reacts with carbonates to form CO2 React with acids to neutralise them 3. e.g. HCl e.g. NaOH

Theories of Acids & Bases Limitations

Arrhenius: acids give H+ ions in aqueous solution and bases give OH- ions in aqueous solution.

Only limited to aqueous solutions.

Cannot explain how CO2, SO2 are acids or NH3, Na2CO3 are bases.

Bronsted-Lowry: acids are proton donor & bases are proton acceptor.

AlCl3, BF3, SnCl2 are acids.

Lewis: acid is an e- acceptor & a base is an electron donor.

It fails to assign the strength of acids & bases.


Indicators for testing acids and bases:

Indicator Colour changes in acid Colour changes in base

Litmus paper Blue litmus turns red Red litmus turns blue

Methyl Orange Red in acidic solution Yellow in basic solution

Phenolphthalein Turns colurless Turns pink

pH value : for determining the strength of acids and bases.

pH = -log[H+]

Importance of pH

a. In agriculture : by determining the type of the soil and deciding on

fertilisers to be used and crop to be sown.

b. In biological processes : by knowing the pH, we can adjust the medium

of biological processes like fermentation, enzyme hydrolysis,

sterilization etc.

c. In corrosion research : by measuring the pH of sea-water, the effect of

alkaline sea-water on the material used for building ships and

submarines is studied.

Buffer Solution: a solution whose pH does not change when small amount of an

acid or a base is added in it. Its of three types:

a. Simple Buffer- weak acid + weak base e.g. CH3COONH4 , amino acids.

b. Acidic buffer-weak acid + its conjugate base or its salt formed with strong

base e.g. mixture of acetic acid & sodium acetate.

c. Basic Buffer- weak base + its conjugate acid or i ts salt formed with strong acid

e.g. mixture of NH4OH and NH4Cl in equimolar quantities.


SALTS PREPARATIONS USES

Common Salt NaCl

NaOH + HCl -> NaCl + H2O -Preservative in pickle, for cooking -Manufacture soap

Sodium Hydroxide

Electrolysis of brine 2NaCl + 2H2O -> 2NaOH + CL2 + H2

-Textile fibre Manufacture Paper -Oil Refining

Washing Soda (Na2CO3.10H2O)

NaCl + NH3 + H2O + CO2 -> NaHCO3 + NH4Cl

2NaHCO3 -> Na2CO3 + CO2 + H2O Na2CO3 + 10H2O -> Na2CO3.10H2O

-Cleansing Agent -Remove hardness of water -Manufacture glass

Baking Soda (NaHCO3)

NaCl + NH3 + H2O + CO2 -> NaHCO3 + NH4Cl

-Used as antacid - fire extinguishers -cakes & breads

Bleaching powder or chloride of lime (CaOCl2)

Ca(OH)2 + Cl2 -> CaOCl2 + H2O Passing chlorine gas over dry slaked lime

-disinfecting drinking water -manufacture chloroform -making wool unshrinkable.

Plaster of Paris CaSO4.1/2H2O

CaSO4.2H2O -> CaSO4.1/2H2O + 3/2H2O (gypsum)

-setting fractured bone, toys etc. - its fire-proof


METALS AND NON-METALS

Physical Properties

METALS NON-METALS

Malleable* & Ductile** Yes No, they are brittle

Hardness Generally hard except Na & K

Generally sift except diamond

Good conductors of heat Yes except lead No

Good conductors of electricity Yes except iron & mercury

No except graphite used for electrodes

Lustrous Yes No except iodine

Sonorous Yes No

State at room temperature Generally solid May be any

Melting & boiling points High except Na, K Low

Density High except Na, K Low

*Malleable : can be thinned about sheets. **Ductile : can be drawn into wires.

Chemical Properties METALS NON-METALS

With oxgen Form basic or amphoteric oxides (those who show both acidic and basic behaviours e.g. Al2O3 and ZnO2)

Form acidic or neutral oxides e.g. CO2, H2O.

With water Form oxide or hydroxides and produce hydrogen gas

No reaction

With acids Only those metals displace hydrogen which are above hydrogen in the reactivity series 2Na + 2HCl -> 2NaCl + H2 Cu + HCl -> no reaction

No reaction

With salt solutions higher reactive metals displaces lesser reactive one CuSO4 + Zn -> ZnSO4 + Cu

More reactive non-metal displaces less reactive one 2NaBr + Cl2 -> NaCl + Br2

With Chlorine Electrovalent chlorides : NaCl Covalent chlorides eg. HCl

With Hydrogen Metal hydrides eg. NaH Covalent hydrides eg. H2S


Reactivity Series of Metals:

Potassium K (Most Reactive Metal)

Sodium Na

Calcium Ca

Magnesium Mg

Aluminium stronger than hydrogen => Al

Zinc displaces hydrogen from its Zn

Iron compounds like water/acids Fe

Tin Sn

Lead Pb

Hydrogen H

Copper Cu

Mercury Hg

Silver less reactive than hydrogen Ag

Gold Au (Least Reactive)

Metalloids : which exhibit some properties of metals and some other properties

of non-metals. Eg. Boron, Silicon & Germanium.

Minerals & Ores :

The natural materials in which the metals or their compounds are found in earth

are called minerals. Those minerals from which the metal can be extracted

conveniently and profitably are ores.

Relative Abundance of metal on earth : Al > Fe > Ca > Na > K > Mg > Ti

The various process involved in extraction of metals from their ores and refining :

a. Concentration of ore/ benefication : removing unwanted material by

Hydraulic washing : difference in density of ore & gangue

Magnetic Separation

Froth floatation process : for sulphide ores

Leaching : ore is treated with suitable re-agent which dissolves ore

leaving behind impurities. This is used for bauxite. (Al ore)

b. Calcination: the process of heating ore below its melting point in the

presence of air to remove impurities and convert into metal oxides.


c. Reduction of metal oxide to metal.

(when Aluminium powder is used, its called thermite reaction)

d. Refining . purification of metals through

o electrolyte refining : used for Cu, Au, Ag, Pb , Zn and Al.

o Liquidation: those metals which have impurities with melting point

higher than metal.

o Distillation : purify those which have low boiling points eg. Na, K, Zn

and Hg (mercury).

Few related terminologies:

1. Gangue : impurities (undesirable particles)

2. Flux : substance added to ore to remove gangue

3. Slag : gangue +flux

4. Smelting : the process of heating ore above its melting point in excess air to

obtain pure metal.

5. Sintering : the process of crushing ore to reasonable size before concentration

of ore.

6. Thermite Reaction: the reduction of metal oxide to form metal by using

aluminium powder as a reducing agent is called thermite reaction.

7. Anodising: the process of forming a thick layer of aluminium oxide on an

aluminium object by making it anode during the electrolysis of dilute sulphuric

acid. This protects aluminium from further corrosion.

8. Galvanisation: is the process of applying a protective zinc coating to steel or

iron, to prevent rusting.

9. Quenching: Steel is heated to bright redness and then suddenly cooled in

water or oil, it becomes extra-ordinary had and brittle.

10. Annealing: Steel is heated to a temperature well below red hot and then

cooled which turns it soft.

11. Tempering: By controlled heating of quenched steel (22-350 degree Celsius),

its brittleness can be removed without affecting its hardness.

Hardness of Water: water which does not easily form lather with soap is known

as soft water. The hardness of water is due to presence of soluble salts of calcium

and magnesium.


Note soaps are sodium salts of fatty acids.

Temporary hardness caused due to bicarbonates of calcium and magnesium can be

removed by boiling or adding lime.

Permanent hardness caused by chlorides and sulphates of calcium and magnesium

can be removed by adding caustic soda or washing soda.

Alloys

Homogenous mixture of 1 or more metals thus improving the various properties

(strength, hardness, resistance to corrosion, electrical conductivity, melting point) of

metals in the combination.

Alloys Composition Uses

Duralumin Al + Cu + Mg + Mn

For making pressure cooker, aeroplanes

Magnalium Al + Mg To make balance beams and light instruments

ALNICO Al + Ni + Co + Fe For making magnets

Stainless steel

Fe + Cr + Ni + C Utensils, surgical cutlery

Nickel Steel Fe + Ni Electrical wire, automobile parts

Steel Fe + C Nails, screws, bridges and railway lines

Brass Cu + Zn Decorative material, handles

Bronze Cu + Sn Statues, coins and medals

German silver Cu + Zn + Ni Ornaments

Rolled gold Cu + Al Cheap ornaments

Gun metal Cu + Sn + Zn + Pb Gun, barrels, gears and bearing

Dutch metal Cu + Zn Artificial jewellery

Solder Pb + Sn Soldering wire together

Amalgam Hg + others Used by dentist for filling in teeth


CARBON AND ITS COMPOUNDS

Allotropy : Substances which have same chemical property but different physical

properties are known as Allotropes and this property is known as Allotropy.

Allotropes of Carbon:

a. Diamond

Hardest

Bad conductor of heat & electricity

High melting point

High density

b. Graphite

Good conductor of heat and electricity

Insoluble in ordinary solvent.

c. Charcoal : obtained from wood, sugar, animal bones

d. Coke : used for manufacturing water gas, household fuel, manufacturing

graphite.

It is also used in the extraction of metals such as iron, copper, tin, zinc as it is

an excellent reducing agent.

Types of Organic Compounds:

1. Saturated Hydrocarbons: containing single bonds (alkanes).

Unsaturated Hydrocarbons: containing atleast 1 double or triple bond (alkenes,

alkynes).The addition of hydrogen to an unsaturated hydrocarbon (e.g. oil) to

obtain a saturated hydrocarbon (e.g. ghee) is called hydrogenation.

2. Haloalkanes (-Cl, -Br, -F, -I)

3. Alcohols (-OH)

4. Aldehydes (-CHO)

5. Ketones (-CO-)

6. Carboxylic acid (-COOH)

7. Ester (-COOR, where R is an alkyl group): formed by carboxylic acid and alcohol

8. Amino acids (-NH2)

9. Nitro group (-NO2)


Isomers : the organic compounds having same molecular formula but different

structure are called isomers e.g. structural isomers of propanol (C3H7OH)

Note that when acetylene and pure oxygen are burned, then acetylene burns

completely producing a blue flame with high heat. This oxy-acetylene flame is used

of welding.

Unsaturated Cyclic hydrocarbon : Benzene C6H6 (aromatic compound)

Polymerization : the process of formation of big molecule (polymer) by the

combination of a large number of molecules (its monomers).

Polymers are backbone of 4 major industries : plastics, elastomers, fibres and

paints.


Thermoplastic polymers Thermosetting polymers

These are neither very strong nor very weak and have no cross-links between the chains.

These are cross-linked.1

They are linear or slightly branched. These are heavily branched. They are capable of softening on

heating and hardening on cooling On heating, it undergoes extensive

cross linking between polymer chains to give a 3D solid and again become infusible.

e.g. polythene, polystyrene, poly vinyl chloride

Bakelite, urea-formaldehyde resins etc.

Natural Rubber (elastomer): obtained from latex.

Vulcanisation of rubber: This process consists of heating a mixture of natural

rubber with sulphur at a temperature range between 373K to 415K. After this

process, sulphur forms cross-linked at the reactive sites of double bonds and thus

rubber becomes hard and more flexible.

Synthetic Rubber: is vulcanizable rubber which is capable of getting stretched to

twice its length. When it is released, it re-gains its shape and size.

Saponification: process of making soap by hydrolysis of fats and oils with alkalis.

Polymers Its Monomer Uses

Nylon HOOC-(CH2)4- COOH & H2N-(CH2)-NH2

Making sheets, bristles for brushes, textile industry

Poly propene

CH2=CH- CH2 Manufacturing ropes, toys, fibre and pipes

Polystyrene Benzene-CH= CH2 As insulator, manufacturing of TV cabinets and radio

Polyvinyl chloride

CH2=CH-Cl Manufacturing of Raincoats, hand bags, water pipes

Bakelite Phenol (benzene-OH) & HCHO formaldehyde

For making of combs of electrical switches, handles of utensils


TEST YOUR UNDERSTANDING

Part I

1 Q) Which of the following is the lightest metal?

(a) Mercury (b) Silver (c) Lithium (d) Lead

2 Q) The most important ore of aluminium is

(a) bauxite (b) calamine (c) calcite (d) galena

3 Q) The element present in the largest amount in rocks and minerals is

(a) carbon (b) silicon (c) hydrogen (d) aluminium

4 Q) An alloy used in making heating elements for electric heating devices is

(a) solder (b) alloy steel (c) nichrome (d) German silver

5 Q) German silver is an alloy of

(a) copper, nickel and silver (b) silver, copper and aluminium (c) zinc, copper and nickel (d) silver, zinc and copper


6 Q) Match the following : ABCD will correctly match with

A. Aluminium 1 Monazite

B. Uranium 2 Pitchblende

C. Thorium 3 Bauxite

D. Lead 4 Galena

5 Haematite

(a) 5 3 2 4 (b)3 2 4 1 (c) 3 2 1 4 (d)2 3 1 5

7 Q) Diamond is an allotropic form of

(a) silicon (b)carbon (c) sulphur (d)germanium

8 Q) Air is a/an (a) compound (b) element (c) mixture (d) electrolyte

9 Q) Which of the following is the best conductor of electricity?

(a) Ordinary water (b) Sea water (c) Boiled water (d) Distilled water

10 Q) Balloons are filled with

(a) helium (b) oxygen (c) nitrogen (d) argon


11 Q) The charcoal used to decolourise raw sugar is (a) animal charcoal (b) sugar charcoal (c) coconut charcoal (d) wood charcoal

12 Q) The most abundant metal in the earth’s crust is

(a) zinc

(b) copper

(c) aluminium

(d) iron

13 Q) Production of chlorofluorocarbons (CFC/freon) gas which is proposed to be

banned in India, is used in which of the following domestic products ?

(a) Television

(b) Tubelight

(c) Cooking gas

(d) Refrigerator

14 Q) The gas used to extinguish fire, is

(a) neon

(b) nitrogen

(c) carbon dioxide

(d) carbon monoxide

15 Q) In which of the following activities silicon carbide (corundum) is used ?

(a) Making cement and glass

(b) Disinfecting water of ponds

(c) Making casts for statues

(d) Cutting very hard substances


16 Q) The element common to all acids is

(a) carbon

(b) hydrogen

(c) oxygen

(d) sulphur

17 Q) Gobar gas contains mainly

(a) methane

(b) carbon dioxide

(c) butane

(d) carbon monoxide

18 Q) The most malleable metal is

(a) Silver

(b) Gold

(c) Aluminium

(d) Sodium

19 Q) Tetraethyl lead is used as

(a) mosquito repellent

(b) painkiller

(c) fire extinguisher

(d) petrol additive

20 Q) Which of the following is used in beauty parlours for hair setting?

(a) Chlorine

(b) Sulphur

(c) Phosphorus

(d) Silicon


21 Q) Which one among the following is not a periodic property i.e., does not show

any trend on moving from one side to the other in the Periodic Table?

(a) Atomic size

(b) Radioactivity

(c) Valency

(d) Electronegativity

22 Q) Which one of the following is used as an anti-freezer, which effectively

depresses the freezing point of water in an automobile?.

(a) Ethylene glycol

(b) Propanoic acid

(c) Glutamic acid

(d) Glycolic acid

23 Q) Aqua-regia used by alchemist to separate silver and gold is a mixture of

(a) concentrated HNO, and concentrated H2SO4

(b) concentrated HC1 and concentrated H2SO4

(c) concentrated HN03 and concentrated HCl

(d) dilute HN03 and dilute HCl

24 Q) "Metal used to make wires for safety fuses must have "

(a) very low resistivity and high melting point (b) high resistivity and low melting point (c) low resistivity and low melting point (d) high resistivity and high melting point

25 Q) Which of the following is not a natural polymer?

(a) Wool (b) Silk (c) Cotton (d) Teflon


26 Q) The ultra pure metal is obtained by

(a) calcination (b) sublimation (c) zone refining (d) None of these

27 Q) Which one among the following polymers is used to make personal armour

such as combat helmets, ballistic face masks, and ballistic vests?

(a) Teflon (b) PVC (c) Bakelite (d) Kevlar

28 Q)

Assertion (A) A buffer solution is a mixture of a strong acid and its conjugate base

or a strong base and its conjugate acid.

Reason (R) Buffer solutions keep the pH at a nearly constant value.

(a) Both A and R are true and R is the correct explanation of A (b) Both A and R are true but R is not the correct explanation of A (c) A is true but R is false (d) A is false but R is true

29 Q) Which of the following gases in the atmosphere is/are responsible for acid

rains?

I. Oxides of sulphur

II. Oxides of nitrogen

III. Oxides of carbon

Select the correct answer using the codes given below

(a) I and II (b) I and III (c) Only II (d) All of these


30 Q) Match the Following

List l List II

(Elements) (Ores/Minerals)

A. Copper 1. Corundum, Bauxite

B. Iron 2. Malachite, Azurite

C. Lead 3. Galena, Lanarkite

D. Aluminium 4. Haematite,Limonite

(a) 2 4 3 1 (b) 2 3 4 1 (C) 4 3 1 2 (d) 4 1 3 2 31 Q) Vermicompost is a/an (a) inorganic fertilizer (b) toxic substance (c) organic bio fertilizer (d) synthetic fertilizer

32 Q) Which one of the following is involved for desalination of sea water? (a) Simple osmosis (b) Reverse osmosis (c) Use of sodium aluminium silicate as zeolite (d) Use of ion selective electrode

33 Q) Soaps are important cleansing agent and this property is due to their

emulsifying action. How does soap enhance the cleansing action?

(a) It has a strong acidic character which can dissolve the dirt (b) It rises the temperature of the reaction (c) It breaks triple bond formed between dirt and cloth (d) It has capacity to render more prolonged the mixing of oil and water


34 Q) The animal fats undergo 'auto-oxidation' under ordinary temperature which

gives the fats a rancid taste and odour. Which one of the following causes the

rancid taste and odour of the fats?

(a) Platinum (b) Carbon monoxide (c) Carbon dioxide (d) Aldehydes

35 Q) "The pungent smell of garlic is due to "

(a) phosphate compound (b) nitrate compound (c) sulphur compound (d) chlorine compound

36 Q) Which one among the following statement about an atom is not correct? (a) Atoms always combine to form molecule (b) Atoms are the basic units from which molecules and ions are formed (c) Atoms are always neutral in nature (d) Atoms aggregate in large numbers to form the matter that we can see, feel and touch

37 Q) "The light emitted by firefly is due to "

(a) radioactive substance (b) chemiluminiscence process (c) a photoelectric process (d) burning of phosphorus

38 Q) Which one among the following metals is used in fireworks to make a

brilliant white light?

(a) Sodium (b) Magnesium (c) Aluminium (d) Silver


39 Q) "Consider the following statements.

I. In the titration between weak bases and strong acids, the indicator such

as methyl orange is commonly used.

II. In the titration between a weak acid and a strong base, the indicator

such as phenolphthalein is commonly used. Which of the statements

given above is/are correct?"

(a) Only I (b) Only II (c) Both I and II (d) Neither I nor II

40 Q) Which one among the following polymers is used for making bullet-proof

material?

(a) Polyvinyl chloride

(b) Polystyrene

(c) Polyethylene

(d) Polyamide

41 Q) Which one of the following is the softest? (a) Sodium (b) Iron (c) Aluminium (d) Copper

42 Q) Ethanol mixed petrol is being sold in various states wef January 1, 2003. The

percentage of ethanol in petrol is

(a) 10% (b) 7% (c) 6% (d) 5%


43 Q) A polymer which is used for making ropes and carpet fibres is

(a) polyacetylene (b) polypropylene (c) polyacrylonitrile (d) PVC

44 Q) Which one among the following salts causes hardness to the water?

(a) Calcium bicarbonate (b) Calcium carbonate (c) Sodium sulphate (d) Potassium chloride

45 Q) Which one among the following is the natural polymer?

(a) Nylon

(b) Teflon

(c) PVC

(d) Cellulose

46 Q) Vinegar is used as a condiment, and in the pickling of vegetables and other

foods. What is the constituent of vinegar?

(a)Butanoic acid

(b) Methanoic acid

(c) Ethanoic acid

(d) Hexanoic acid

47 Q) Which of the following pesticide is applied to the foundation of buildings to

prevent termites?

(a) Aldrin

(b)Malathion

(c) Atrazine

(d)Carbaryl


48 Q) "Consider the following substances.

I. Cadmium II. Boron III. Nickel

Which of the substances given above is/are used as controlling rod in nuclear

reactor? "

(a) All of these (b) I and II (c) II and III (d) Only II

49 Q) Liquid sodium is used for the heat transfer medium in some of nuclear

reactor because

(a) sodium has high rate of vapourisation

(b) sodium has low density and high viscosity

(c) sodium has high specific heat than the most liquid metals

(d) All of the above

50 Q) Which one of the following petroleum refinery products has the lowest

boiling point?

(a) Kerosene

(b) Gasoline

(c) Diesel

(d) Lubricating oil


ANSWER KEY TO PART I

Ans 1). C Ans 26) C

Ans 2) A Ans 27) D

Ans 3) B Ans 28) D

Ans 4) C Ans 29) A

Ans 5) C Ans 30) A

Ans 6) C Ans 31) C

Ans 7) B Ans 32) B

Ans 8) C Ans 33) D

Ans 9) B Ans 34) D

Ans 10) A Ans 35) C

Ans 11) D Ans 36) D

Ans 12) C Ans 37) D

Ans 13) D Ans 38) B

Ans 14) C Ans 39) C

Ans 15) D Ans 40) C

Ans 16) B Ans 41) A

Ans 17) A Ans 42) D

Ans 18) B Ans 43) B

Ans 19) D Ans 44) A

Ans 20) B Ans 45) D

Ans 21) B Ans 46) C

Ans 22) A Ans 47) A

Ans 23) C Ans 48) B

Ans 24) B Ans 49) C

Ans 25) D Ans 50) B


QUESTIONAIRE PART II

51 Q) Which one of the following is used as a mordant in dyeing and tanning industry? (a) Magnesium oxide (b) Magnesium chloride (c) Magnesium sulphate (d) Magnesium carbonate

52 Q) "The gas used in a refrigerator is "

(a)cooled down on flowing

(b)heated up on flowing

(c)cooled down when compressed

(d)cooled down when expanded

53 Q) Consider the following statements. Loss of beta- particle is equivalent to

I. increase in one proton only.

II. decrease in one neutron only.

Which of the statements given above is/are correct?"

(a) Only I

(b) Only II

(c)Both I and II

(d) Neither I nor II

54 Q) Which one of the following oxides is the most abundant in Earth crust?

(a) Na2O

(b) CaO

(c) MgO

(d) SiO2


55 Q) The flavour of apple is mainly due to which one of the following?

(a) Formalin (b) Ethanol (c) Benzene (d) Benzaldehyde

56 Q) Which one among the following statements is correct?

(a) All bases are alkalis

(b) None of the basis is alkali

(c) There are no more bases except the alkalis

(d) All alkalis are bases but all bases are not alkalis

57Q) KO2 (Potassium superoxide) is used in oxygen cylinders in space and

submarines because it

(a) eliminates moisture (b) absorbs C02 (c) produces ozone (d) produces C02

58 Q) Scuba divers are at high risk due to high concentration of dissolved gases

while breathing air at high pressure under water. The tanks used by Scuba divers

are filled with

(a) air diluted with helium

(b) 02

(c) N2

(d) a mixture of nitrogen and helium

59 Q) "Which one of the following is correct? Setting of plaster of Paris is "

(a) dehydration

(b) oxidation with atmospheric oxygen

(c) hydration leading to another hydrate

(d) combination with atmospheric carbon dioxide


60 Q) Assertion (A) On mixing with water, plaster of Paris hardens.

Reason (R) By combining with water, plaster of Paris is converted into gypsum.

(a)Both A and R are true and R is the correct explanation of A

(b)Both A and R are true but R is not the correct explanation of A

(c)A is true but R is false

(d)A is false but R is true

61 Q) "The bleaching action of chlorine occurs in the presence of "

(a) moisture

(b) sunlight

(c) pure oxygen

(d) pure sulphur dioxide

62 Q) Which one among the following polymers is re-synthesised from the

naturally occurring polymer?

(a) Kevlar

(b) Teflon

(c) Rayon

(d) Cellulose

63 Q) Food wrapped in newspaper is likely to get contaminated with

(a) aluminium

(b) lead

(c) iron

(d) magnesium

64 Q) Which one of the following has been producing/can produce light by a

chemical change?


(a) Electric bulb

(b) Moon

(c) Sun

(d) Lightning and thunder

65 Q) Which one of the following chemical compounds is responsible for the

stimulation of tear glands by the onion?

(a)A phosphate compound

(b)A nitrate compound

(c)A sulphide compound

(d)A chloride compound

66 Q) "Many communities put salt on their roads after a snowfall, Why? "

(a)To enhance the freezing and hardening of snow

(b)To control the slipping of vehicles

(c)To keep the melted snow from refreezing

(d)None of the above

67 Q) Assertion (A) All liquids are conductors of Electricity.

Reason (R) Under the condition of low pressure and high voltage, liquids can be

made conducting."





68 Q) Which one among the following would expand the most on being heated?

(a) Water

(b) Air

(c) Alcohol

(d) Glass


69 Q) "Consider the following statements

I. Glass wool has tensile strength greater than steel,

II. Glass wool is fire powder.

III. Glass wool has high electrical conductivity and absorbs moisture.

IV. Glass wool is used to prepare fire glass.

Which of the statements given above are correct?"

(a)I, II, III and IV

(b) I, II and III

(c) I, II and IV

(d) III and IV

70 Q) Why hard water does not give lather with soap?

(a) Hard water contains calcium and magnesium ions, which form precipitate with

soap

(b) Hard water contains sulphate and chloride ions, which form precipitate

(c) pH of hard water is high

(d) pH of hard water is less

71 Q) The most abundant metal in the Earth's crust is

(a) Si

(b) Fe

(c) Al

(d) Cu

72 Q) If four balloons A, B, C and D are filled with hydrogen, oxygen, helium and

nitrogen gases respectively and left in air, which balloon reaches to the highest

distance from the Earth?.

(a) Balloon A

(b) Balloon B

(c) Balloon C

(d) Balloon D


73 Q) Which one of the following is used in the preparation of antiseptic solution?

(a)Potassium nitrate

(b)Iodine

(c)Iodine chloride

(d)Potassium chloride

74 Q) Contact lenses are made from

(a) polyvinyl chloride

(b) polystyrene

(c) Teflon

(d) lucite

75 Q) Which one among the following substances evolved heat when dissolved in

water?

(a) Glucose

(b) Fructose

(c) Quick lime

(d) Salt peter

76 Q) The biological specimens in laboratory are preserved in the glass containing

formalin. What is the "formalin''?

(a)An aqueous solution of H2S04

(b)An aqueous solution of HNOa

(c)An aqueous solution of formaldehyde

(d)Concentrated solution of HNOa

77 Q) "Consider the following statements

I. Photochromatic lenses darken on exposure to ultraviolet light.

II. Photochromatic properties is due to embedded microcrystalls of silver

chloride in the glass.


Which of the statements given above is/are correct?."

(a)Only I

(b) Only II

(c)Both I and II



List 1 (Names) List II (Compounds)

A. Baking soda 1. Sodium nitrate

B. Washing soda 2. Calcium hydroxide

C. Chile saltpeter 3. Sodium carbonate

D. Slack lime 4. Sodium bicarbonate

(a) 2 4 3 1

(b) 2 3 4 1

(c) 4 3 1 2

(d) 4 1 3 2


List 1 (Polymers) List II (Monomers)

A. Nylon-6 1. para-phenylenediamine + Terephthaloyl chloride

B. Kevlar 2. Caprolactum

C. Nylon-66 3. Hexamethylene diamine + Adipic acid

D. Bakelite 4. Phenol + Formaldehyde

(a) 2 1 3 4

(b) 2 3 4 1

(c) 3 4 2 1

(d) 3 1 2 4


80 Q) The rusting of iron nail

(a) decreases it weight

(b) increases its weight

(c) does not affect weight but iron is oxidised

(d) does not affect weight but iron is reduced

81 Q) Which one of the following is the hardest alkali metal?

(a) Li

(b) K

(c) Na

(d) Cs

82 Q) "What is the role of positive catalyst in a chemical reaction? "

(a) It increases the rate of reaction

(b) It decreases the rate of reaction

(c) It increases the yield of the products

(d) It provides better purity of the products

83 Q) The pH of fresh groundwater slightly decreases upon exposure to air because

(a) carbon dioxide from air is dissolved in the water

(b) oxygen from air is dissolved in the water

(c) the dissolved carbon dioxide of the groundwater escapes into air

(d) the dissolved oxygen of the groundwater escapes into air

84 Q) What is the purpose of adding baking soda to dough?.

(a)To generate moisture

(b)To give a good flavour

(c)To give a good colour

(d)To generate carbon dioxide


85 Q) Which one among the following agents is added to domestic LPG cylinder to

help in the detection of gas leakage?

(a) Methano

(b)Ethanol

(c) Thioethanol

(d)Chloroform

86 Q) To meet its rapidly growing energy demand, some opine that India should

pursue research and development on thorium as the future fuel of nuclear energy.

In this context, what advantage does thorium hold over uranium?

1. Thorium is far more abudant in nature than uranium

2. On the basis of per unit mass of mined mineral, thorium can generate more

energy compared to natural uranium.

3. Thorium produces less harmful waste compared to uranium.

Which of the statement (s) given above is/are correct?"

(a) Only 1

(b) 2 and 3

(c) 1 and 3

(d) 1, 2 and 3

87 Q) Which one among the following will you put into pure water in order to pass

electric current through it?

(a) Kerosene

(b) Mustard oil

(c) Sugar

(d) Lemon juice

88 Q) Which one of the following is the metallurgical operation in which a metal is

obtained in a fused state?

(a) Calcination

(b)Roasting


(c) Froth floatation

(d)Smelting

89 Q) "Carbonated beverages such as soft drinks and soda water contains mainly "

(a) carbon dioxide

(b) calcium carbonate

(c) calcium hydroxide

(d) potassium carbonate

90 Q) Assertion (A) Nitric acid is used in the production of fertilizers.

Reason (R) Sulphuric acid is used in the production of explosive."





91 Q) Which one among the following when dissolved in water give hissing sound?

(a) Limestone

(b)Sodalime

(c) Slaked lime

(d)Quick lime

92 Q) "Consider the following substances I. Heavy Water II. Graphite

Which of the substances given above is/are used as a moderator in a nuclear

reactor? "

(a) Only I

(b) Only II

(c) Both I and II



93 Q) Which of the following pairs of chemical compounds has the potential for

carbon capturing by chemical process to reduce the global warming?

(a)Potassium oxide and sodium oxide

(b)Magnesium oxide and calcium oxide

(c)Magnesium oxide and potassium oxide

(d)Calcium oxide and potassium oxide

94 Q) Assertion (A) The nuclear fusion reaction releases less energy than the fission

reaction.

Reason (R) The nuclear fusion reaction takes place in the sun and other stars.





95 Q) "Consider the following gases

I. Water vapour

II. Nitrous oxide

III. CFC

IV. Methane

Which of the gases given above are “Green House Gases (GHGs)”? "

(a) All of these

(b) I, II and III

(c) II and III

(d) II and IV

96 Q) Electronegativity is the ability of an atom in a chemical compound io attract

shared electrons towards itself where as Electron Gain Enthalpy is the amount of

energy released when an isolated neutral gaseous atom of the element takes up


extra electron to form a uni-negative gaseous ions, also called electron affinity. tell

the element with highest electronegavity and the one with highest electron

affinity?

(a) Fluorine, Chlorine

(b) Chlorine, fluorine

(c) Iodine, Fluorine

(d) Fluorine, fluorine


List 1 List II

(Elements) (Colour on flame)

A. Barium 1. Yellow

B. Sodium 2. Greenish

C. Silver 3. Turns black

D. Lead Codes 4. Apple green

(a) 2 4 3 1

(b) 2 3 4 1

(c) 4 3 1 2

(d) 4 1 3 2

98 Q) Making of chappathi is based on

(a) Graham's law

(b) Henry's law

(c) Charles' law

(d) Boyle's law


99 Q) The hair dye available in the market contains two bottles, one containing dye

and other containing hydrogen peroxide. The bottles are mixed before applying the

dye. The function of hydrogen peroxide is

(a) to dilute the dye

(b) to oxidise the dye to give desired colour

(c) to reduce the dye to give desired colour

(d) to acidify the dye solution

100 Q) From which one among the following water source, the water is likely to be

contaminated with fluorine?

(a) Ground water

(b) Rain water

(c) River water

(d) Pond water


ANSWER KEY TO PART II

Ans 51) C Ans 76) C

Ans 52) D Ans 77) C

Ans 53) C Ans 78) C

Ans 54) D Ans 79) A

Ans 55) B Ans 80) B

Ans 56) D Ans 81) A

Ans 57) B Ans 82) A

Ans 58) A Ans 83) A

Ans 59) D Ans 84) D

Ans 60) A Ans 85) C

Ans 61) A Ans 86) D

Ans 62) C Ans 87) D

Ans 63) B Ans 88) D

Ans 64) C Ans 89) A

Ans 65) C Ans 90) B

Ans 66) C Ans 91) D

Ans 67) D Ans 92) C

Ans 68) B Ans 93) B

Ans 69) C Ans 94) D

Ans 70) A Ans 95) A

Ans 71) C Ans 96) A

Ans 72) B Ans 97) D

Ans 73) B Ans 98) C

Ans 74) D Ans 99) B

Ans 75) C Ans 100) C

Chemistry capsule

Documents

Transcript of Chemistry capsule