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SECOND YEAR IPE CHEMISTRY IMPORTANT QUESTIONS ` KKP / MYP CENT RE

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VERY SHORT ANSWER QUESTIONS

SOLID STATE Previous Year Questions

1. Explain Antiferromagnetism with suitable examples.

Ans. Substances like MnO showing anti-feromagnetism having domain structure similar to ferromagnetic substance, but their domains are oppositely oriented and cancel out each other magnetic moment.

2. Why ionic solids are hard and brittle.

Ans. In ionic solids the formation of solid compound is due to the arrangements of cations and anions bound by strong coloumbic force i.e., electro static force. So ionic solids are hard and brittle in nature. These have high melting and boiling points.

3. Stability of a crystal is reflected in the magnitude of its melting point. Comment.

Ans. Stability of a crystal is reflected in the magnitude of its melting point.

Explanation:

i) The stability of a crystal mainly depends upon the magnitude of forces of attraction between the constituent particles.

ii) As the attractive forces between the constituent particles increases stability of the crystal also increases.

iii) As the stability of crystal increases melting point of solid will be higher.

4. Define the term amorphous.

Ans. An amorphous solid is the compound which does not have orderly arrangement of particles. In amorphous solids the constituent particles, atoms, molecules has short range order only. Amorphous solids are isotropic in nature.

E.g.: Glass, rubber, plastics etc

5. How do you distinguish between hexagonal close-packing and cubic close packing structures.

Ans. Hexagonal close packing: The spheres of the 3rd layer are exactly aligned with those of first layer. This pattern is repeated in alternate layers. Tetrahedral voids of the 2nd layer may be covered by the spheres of 3rd layer. This structure is called hexagonal close packed (hcp) structure. Cubic close packing: The spheres of 3rd layer cover the octahedral voids of 2nd layer. But the spheres of 4th layers are aligned with those of first layer. This structure is called cubic close packing. Hexagonal close packing has ABABABAB…… pattern arrangement. Cubic close packing has ABCABC…… pattern arrangement.

6. Classify the following solids as ionic, metallic, molecular, covalent network (i) Si (ii) I2 (iii) P4 (iv) Rb

Ans. (i) Si - Covalent network solid (ii) I2 - Molecular solid with covalent bonds

(iii) P4 - Molecular solid with covalent bonds (iv) Rb - Metallic solid

7. What are Schottky defects in crystalline solids?

Ans. Schottky defect:

1) “It is a point defect in which an atom or ion is missing from its normal site in the lattice”.

2) In order to maintain electrical neutrality, the number of missing cations and anions are equal.

3) This sort of defect occurs mainly in highly ionic compounds, where cationic and anionic sizes are similar.

In such compounds the coordination number in high. Ex: NaCl,CsCl, etc

4) Illustration:

5) This effect decreases the density of the substance.


8. How do you distinguish between crystal lattice and unit cell?

Ans. Crystal lattice: A regular arrangement of the constituent particles of a crystal in the three dimensional space is called crystal lattice.

Unit cell: The simple unit of crystal lattice which when repeated again and again gives the entire crystal of a given substance called unit cell.

9. What are the characteristics (a, b, c and , , values) in a tetragonal system?

Ans. Characteristics of tetragonal system: a b c ; 90 Ex: 2SnO

10. What is Tetrahedral hole?

Ans. Tetrahedral hole: A hole formed by three spheres of a layer in contact with each other and another sphere of next layer of a crystal.

11. Calculate the number of particles present in a fcc crystal structure.

Ans. Number of particles present in fcc unit cell: particles occupy six face centres (1

6 32

) and one body

centre 1 1 1 so total effective number of particles = 4.

12. What are octahedral holes? How are they formed?

Ans. Octahedral holes: It is the hole in a crystal surrounded by six spheres lying at the vertices of a regular octahedron.

13. What is meant by Frenkel and Schottky defects?

Ans. Frenkel defect:. It is a point defect due to displacement of atom or ion from its regular position in a crystal. Ex. AgBr

Schottkey defect: It is a point defect due to missing of equal number of cations, anions from their

regular positions in the crystal. Ex. NaCl

14. What is Doping?

Ans. Doping: It is the method of adding an impurity to a semi conductor to enhance its conductivity ex. P or B is used for doping Si.

Additional Very Important Questions

15. What makes a glass different from quartz

Ans. Quartz is Crystalline solid where it has long range order of SiO2 units Glass is amorphous solid where it has short range order of same units.

16. Classify the following solid as ionic, metallic, molecular, covalent network or amorphous.

(i) Si (ii) I2 (iii) P4 (iv) Rb

(v) SiC (vi) LiBr (vii) Ammonium phosphate(NH4)3PO4

(viii) Plastic (ix) graphite (x) tetra phosphorous decoxide (xi) brass

Ans. Si – Covalent network

I2 – Non - polar molecular solid

P4 – Non - polar molacular solid

Rb – Metallic solid

SiC – Covalent or Network solid

LiBr – Ionic Solid

(NH4)3PO4 – Ionic solid

Plastic – Amorphous

Graphite – Covalent or Network solid

P4O10 – Molecular solid

Brass – Metallic solid

17. What are F-centres?

Ans. The anionic sites occupied by unpaired electrons are called F-centres.


18. Explain Ferromagnetism with suitable example.

Ans. The substance which is very strongly attracted by a magnetic field is ferromagnetic substance.

Eg: Fe, Co, Ni, Gd, CrO2

19. Explain Paramagnetism with suitable example.

Ans. A substance which is weakly attracted by a magnetic field is known as paramagnetic substance.

Eg: O2, Cu+2, Fe+3, Cr+3

20. Explain Ferrimagnetisms with suitable example.

Ans. A substance which is weakly attracted by magnetic field as compared to ferromagnetic substance and is observed when the magnetic moments of the domains in the substance are aligned in parallel and anti-parallel directions in unequal numbers.

Eg: Fe3O4, MgFe2O4, NiFe2O4

SOLUTIONS

Previous Year Questions

21. What is ppm of a solution?

Ans. ppm-parts per million: It is a convenient method of expressing concentration when a solute is present in trace quantities. Parts per million is defined as the

6Number of parts of the componentppm 10

Total no. of parts of all components of the solution

22. What is Ebullioscopic constant?

Ans. Ebullioscopic constant: The elevation of boiling point observed in one molal solution containing non-volatile

solute is called Ebullioscopic constant (or) molal elevation constant.

23. Given an example of a solid solution in which the solute is solid.

Ans. Example of a solid solution in which the solute is solid, is copper dissolved in gold.

24. Calculate the mole fracion (x) of 98% of H2SO4 by mass.

Ans. Given a solution containing – 98% H2SO4 by mass.

It means 98 gms of H2SO4 and 2 gms of H2O mixed to form a solution.

2 4H SO

Weight 2 1n

GMW 18 9

2 4H SO

Weight 98n 1

GMW 98

Mole fraction of H2SO4, 2 4

2 4

2 2 4

H SOH SO

H O H SO

n 1 9X 0.9

n n 1/ 9 1 10

25. State Raoult’s law.

Ans. i) Raoult’s law for volatile solute: For a solution of volatile liquids, the partial vapour pressure of each component of the solution is directly proportional to its mole fraction present in solution.

ii) Raoult’s law for non-volatile solute: The relative lowering of vapour pressure of dilute solution containing

non-volatile solute is equal to the mole fraction of solute.

26. Calculate the mole fraction of sodium hydroxide in 10% w/W NaOH solution.

Ans. 10% w

NaOHW

solution means

10 gms of NaOH in 90 gms of water

2NaOH H O

10 1 90n ;n 5

40 4 18

2

NaOHNaOH

NaOH H O

n 0.25 0.25X 0.048

n n 0.25 5 5.25


27. Define Osmotic Pressure.

Ans. Osmotic pressure: It is the excess pressure that has to be applied on dil. solution to prevent osmosis when it is separated from pure solvent by semi permeable membrane. CST .

28. 4 gm of NaOH are dissolved in 4 litres of the solution. Find the Molarity of the solution.

Ans. Molarity of solution containing 4 gm NaOH dissolved in 4 lit solution.

W 1000 4 1000

M 0.025MGMW V ml 40 4000


29. State Henry’s law.

Ans. The partial pressure of the gas in vapour phase (P) is proportional to the mole fraction of the gas (X) in the solution.

P = KH . X

KH = Henry Law Constant

30. What are isotonic solutions?

Ans. The solutions which exert same osmatic pressure are known as ISOTONIC solutions.

Eg: 0.1 M glucose solution and 0.1 M Urea solution are isotonic.

31. Calculate the amount of benzoic acid (C6H5COOH) required for preparing 250 ml of 0.15M solution in methanol.

Ans. W 1000

MGMW V (ml)

W 1000

0.15122 250

W 4.575g

32. What is Van’t Hoff’s factor ‘t’ and how is it related to ‘ ’ in the case of a binary electrolyte (1:1)?

Ans. The Von’t Hoff factor is defined as

Total Number of molecules after association / dissociation

iTotal Number of molecules before association / dissociation

For Binary electrolyte

2

i1

33. What is relative lowering of vapour pressure?

Ans. The Relative lowering of vapour pressure is equal to mole fraction of the solute.

0A

0

P PX

P

(or) 0 A

0 B

P P n

P n

0P = Vapour of pure solvent

P = Vapour pressure of solution

AX = Mole fraction of solute

34. Calculate the mole fraction of H2SO4 in a solution containing 98% H2SO4 by mass.

Ans. 2 4H SOW 98g

2H OW 2g

2 4H SO

98n 1

98 ;

2 4H SO2

n 0.1118

; 2 4H SO

1X 0.9

1.11


ELECTRO CHEMISTRY


35. How is E0 cell related mathematically to the equilibrium constant KC of the cell reaction?

Ans. Relation between E0 cell and equilibrium constant KC of the cell reaction.

0(cell) c

2.303RTE logK

nF

n = number of electrons involved

F = Faraday = 96500 C mol–1

T = Temperature

R = gas constant

36. Define molar conductivity m∧ and how it is related to conductivity (k)?

Ans. Molar conductivity: The conductivity of a volume of solution containing one gram molecular weight of the electrolyte placed between two parallel electrodes separated by a distance of unit length of 1 meter is called molar conductivity m∧ .

Relation between conductivity and molar conductivity : mk

; c constantc

∧

37. Write the Nernst equation for the EMF of the cell.

2

s aq aqNi | Ni || Ag | Ag

Ans. Nernst equation for the cell is

0cell cell 2

AgRTE E ln

nF Ni

38. What is galvanic cell? Give one example.

Ans. Galvanic cell: A device which converts chemical energy into electrical energy by the use of spontaneous

redox reaction is called Galvanic cell (or) voltaic cell. Ex: Daniell cell.

39. How is change in Gibbs energy G related to the emf (E) of a galvanic cell?

Ans. Relation between Gibb’s energy (G) and emf (E) mathematically

(cell)G nFE

G = change in Gibb’s energy

n = number of electrons involved

F = Faraday= 96500Cmol –1


40. Write the cell reaction taking place in the cell

Cu(s)/ Cu2+ (aq)//Ag+ (aq)/ Ag(s)

Ans. Oxidation Half Reaction 2Cu / Cu

Reduction Half Reaction Ag / Ag

The cell reaction is 2Cu 2Ag Cu 2Ag

41. What is standard hydrogen electrode?

Ans. Standard Hydrogen Electrode is a reference electrode. Which consists of a Pt electrode coated with Pt block which is dipped in 1M HCl and pure H2 gas is bubbled through it, at 1 atm.

42. Write the cell reaction for which 2

0cell cell 2

RT [Mg ]E E ln

2F [Ag ]

Ans. The cell reaction can be represented as 2Mg 2Ag Mg 2Ag

Cell Reaction is 2Mg / Mg / /Ag Ag


43. What is metallic corrosion? Give one example?

Ans. Coating of metallic surface with oxides or other salts of the metal is known as Corrosion.

Eg: rusting of Iron

22 2 2 3 2

32Fe xH O O Fe O .xH O

2

CHEMICAL KINETICS


44. Give two examples of gaseous first-order reactions.

Ans. The following are the examples for gaseous first order reactions.

2 5(g) 2 4(g) 2(g)1

N O N O O2

2 2 2(g) 2(g)SO Cl SO Cl

45 Define order of reaction.

Ans. Order of a reaction: It is the sum of the powers of the concentration terms in the rate equation of the reaction.

46. Define Rate of reaction.

Ans. Rate of reaction: Change in molar concentration of either reactants or products per unit time (sec) unit

– moles 1 1lit sec .

47. Define “Order” and “Molecularity” of a reaction.

Ans. Order: It is the sum of the exponents of concentration terms involved in rate equation.

Molecularity: It is the total number of atoms or ions or molecules involved in the rate determining step of a reaction.


48. What are complex reactions? Name one complex reaction? What is rate determining step in a complex reaction?

Ans. The reaction which involve sequence of elementary reactions for the conversion of reactants into products is called complex reaction. In complex reactions molecularity is equal to 3 or greater than 3.

Ex: 3 4 2 4 2 4 23KClO 6FeSO 3H SO KCl 3Fe SO 3H O

The slowest step in multi step reaction is called rate determining step.

49. What is the effect of temperature on the rate constant?

Ans. For a chemical reaction with rise in temperature by 100 C, the rate constant is nearly doubled.

50. What is pseudo first order reactions? Give one example?

Ans. The bimolecular reactions in which one of the reactant taken in excess are pseudo first order reactions. In pseudo first order reaction molecularity = 2 and order = 1.

Ex: Ester hydrolysis

H3 2 5 2 3 2 5CH COOC H H O CH COOH C H OH

1 03 2 5 2Rate K CH COOC H [H O]

Order with respective ester is first order.

Order with respective water is zero order.


51. What is half life? Write the equation useful to calculate half-life (H/2) values for zero and first order reactions.

Ans.

52. What is activation energy?

Ans. The additional amount of energy absorbed by the reactant molecules so that their energy becomes equal to threshold energy value is called activation energy.

53. Write the Arrhenius equation for the rate constant (k) of reaction?

Ans. k = Ae–Ea /RT A = Arrhenius factor or the frequency factor R = Gas constant Ea = Activation energy measured in J mol–1.

K = rate constant

SURFACE CHEMISTRY

54. What is adsorption? Give one example.

Ans. The accumulation of molecular species on the surface of solid is termed as adsorption.

Ex: Hydrogen gas adsorbed on platinum surface.

55. What is absorption? Give one example.

Ans. The uniform distribution of molecular species into the bulk of a solid is termed as absorption.

Ex: A sponge placed in water absorbs water.

56. The critical temperature of SO2 is 630 K and that of CH4 is 190K. Which is adsorbed easily on activated charcoal? Why?

Ans. SO2 is easily adsorbed on activated charcoal than CH4.

Higher the critical temperature of a gas, more easily it is liquefiable.

Easily liquefiable gases accumulate on the surface of adsorbent with strong intermolecular forces.

57. Amongst SO2 , H2 which will be adsorbed more readily on the surface of charcoal and why?

Ans. As SO2 has higher critical temperature than H2, it is more easily liqufiable and hence more readily adsorbed on the surface of charcoal.

58. Explain why lyophilic colloids are relatively more stable than lyophobic colloids?

Ans. Lyophilic sols are more stable than lyophobic sols. This is due to the fact that lyophilic colloids are extensively solvated, i.e., colloidal particles are covered by a sheath of the liquid in which they are dispersed.

59. What are micelles? Give one example.

Ans. Micelles; Micelle is a colloidal sized particle formed in water due to the association of simple molecules containing a hydrophobic end and a hydrophilic end.

Ex: Sodium stearate in water form micelle

60. Sky appears blue in colour. Explain.

Ans. Sky appears blue in colour due to scattering of light by dust particles. This is due to Tyndall effect.


61. What is Brownian movement?

Ans. The Zig–zag motion of colloidal particles in the dispersion medium is called Brownian movement. It occurs due to unbalanced bombardment of particles by the molecule of the dispersion medium.

62. What is electrophoresis?

Ans. The movement of colloidal particles under the influence of an electric field is called electrophoresis or cataphoresis.

63. Define flocculation value.

Ans. The minimum amount of electrolyte in millimoles that must be added to one litre of a colloidal solution so as to bring about complete coagulation is called the flocculation (or) coagulation (or) precipitation value of the electrolyte.

Thus, smaller is the coagulation value of an electrolyte greater is its coagulating or precipitating or flocculating power.

64. State Hardy – Schulze rule.

Ans. Greater the valence of the coagulating ion added, the greater is its power to cause coagulation. This is known as Hardy – Schulze rule.

65. What is an emulsion? Give two examples.

Ans. The dispersion of finely devided droplets of a liquid in another liquid medium is called an emulsion.

(or)

A colloidal system in which both the dispersed phase and the dispersion medium are liquids, is called an emulsion.

Ex : Milk – In this liquid fat is dispersed in water.

66. Define Gold number?

Ans. Capacity of lyophilic colloid in protecting lyophobic colloid is measured in terms of gold number.

Gold Number is defined as the weight (in mg) of a protective colloid which prevents the coagulation of 10 ml of a given gold sol on adding 1 ml of 10% solution of sodium chloride.

Ex: Gelatin having gold number 0.005 — 0.01.

67. Name the dispersed phase and dispersion medium in the following colloidal systems (i) fog

(ii) smoke (iii) milk.

Ans. Colloidal system Dispersed phase Dispersion medium (i) fog Water droplets Air (ii) Smoke Carbon particles Air (iii) Milk Liquid fat droplets Water

METALLURGY


68. How is leaching carried out in the case of low grade copper ores?

Ans. In case of low grade ores of copper, hydrometallurgy technique is used for extraction. Here leaching

process can be done by using acids (or) bacterial. The solution containing 2Cu is trated with scrap iron

(or) 2H .

2( ) 2( ) 2( ) ( )2aq g s aqCu H H H

69. Why copper matte is put in silica lined converter?

Ans. Copper matte contains Cu2O, sand Fes. In this mixture FeS is gangue. For removing the gangue, silica present in the lining of the Bessemer’s converter acts as acidic flux and forms slag.

2 2gangue2Fes 3O 2FeO 2SO

2 3Gangue flux Slag

FeO SiO FeSiO


70. State the role of silica in the metallurgy of copper.

Ans. The role o silica in the metallurgy of copper is to acts as an acidic flux. Silica reacts with the impurities of

iron and form slag.

Gangue flux Slag

71. Give the composition of the following:

a) German Silver b) Brass

Ans. a) Composition of German silver: 50-60% Cu, 10-30% Ni, 20-30% Zn

b) Composition of Brass: 60-80% Cu, 20-40% Zn

72. What is the role of cryolite in the extraction o aluminium.

Ans. By adding the cryolite to the pure Alumina, the melting point of pure Alumina is lowered (which is very high

2324K) and electrical conductivity of pure alumina is increased.

73. Give the composition of Brass.

Ans. Composition of Brass: 60-80% Cu, 20-40% Zn.


74. What is the role of depressant in froth floatation?

Ans. It is possible to separate a mixture of two sulphide ores by adjusting proportion of oil to water or by using depressants in froth floatation process. For example, in the case of an ore containing ZnS and PbS, the depresent used is NaCN. It selectively prevents ZnS from coming to the froth but allows PbS to come with froth. NaCN forms a layer of Na2[Zn(CN)4] on the surface of ZnS.

75. Explain “poling”.

Ans. Poling is a metal refining process. The molten metal is stirred with logs (poles) of green wood. The impurities are removed as gases. Blister copper is purified by this method. The reducing gases evolved from the wood, prevent the oxidation of copper.

76. How is cast iron different from pig iron?

Ans. The iron obtained from blast furnace contains about 4% carbon and many impurities in smaller amount

(eg: S, P, Si, Mn). This is known as pig iron.

Cast iron is different from pig iron and is made by melting pig iron with scrap iron and coke using hot air blast. It has slightly lower carbon content (about 3%) and is extremely hard and brittle.

77. Explain the terms gangue and slag.

Ans. One is usually contaminated with earthy materials and undesired chemical compounds. These are collectively known as gangue or matrix.

Flux reacts with gangue forming slag. Slag can be removed in the liquid form as it has lower melting point, than gangue.

Flux + gangue slag

Eg. FeO + SiO2 FeSiO3

78. What is blister copper? Why is it so called?

Ans. The solidified copper is obtained by the reaction,

2Cu2O + Cu2S 6Cu + SO2. It has blistered appearance due to evolution of SO2 and so it is called blister copper.

79. What is flux? Give an example.

Ans. During metallurgical operations, substance called flux is used. The added substance ‘flux’ combines with gangue to form slag. Slag separates more easily from the ore than the gangue. Slag has lower melting point than gangue. This can be removed in liquid form.

In the extraction of Copper SiO2 is used as a flux to remove FeO

FeO + SiO2 FeSiO3

Impurity flux slag

Gangue


80. Give two uses each of the following metals.

(a) Zinc (b) Copper (c) Iron (d) Aluminium

Ans. Uses:

a) Zinc

i) Zinc is used for galvanising iron.

ii) Zinc is used as reducing agent in the manufacture of paints, dye-stuff’s etc.

iii) Used in large quantities in batteries.

b) Copper

i) Used in several alloys. Eg: Brass (Cu and Zinc)

ii) Making wires in electrical industry

c) Iron

i) Cast iron is used for casting stoves, railway sleepers, etc.

ii) Wrought iron is used making wires, bolts, agricultural implements.

d) Aluminium

i) Aluminium foils are used as wrapers for chocolates.

ii) Aluminium is used in the extraction of chromium and manganese from their oxides

iii) Aluminium wires are used as electrical conductors.

81. Between C and CO, which is a better reducing agent for Zno?

Ans. Coke is better reducing agent for ZnO and not CO

82. Give the uses of (a) Cast iron (b) Wrought iron (c) Nickel steel (d) Stainless steel

Ans. a) Cast iron is used for casting stoves, railway sleepers, gutter pipes, toys etc.

It is used in the manufacture of wrought iron and steel.

b) Wrought iron is used in making anchors, wires, bolts, chains and agricultural implements

c) Nickel steel is used for making cables, automobiles and aeroplane parts, pendulum measuring tapes.

d) Stainless steel is used for cycles, automobiles, utensils, pens etc.

p – BLOCK ELEMENTS


83. How are 3XeO and 4XeOF prepared?

Ans. 6XeF on hydrolysis produce 3XeO

6 2 3XeF 3H O XeF 6HF

Partial hydrolysis of 6XeF gives 4XeOF

6 2 4XeF H O XeOF 2HF

84. Write any two used of argon.

A. Use of Ar :

1) 'Ar' is used to create inert atmosphere in high temperature metallurgical process

2) 'Ar' is used in filling electric bulbs

85. How is nitrogen prepared in the laboratory? Write the chemical equations of the reactions involved.

A. Preparation of di Nitrogen:

1. Very pure nitrogen is obtained by the thermal decomposition of sodium (or) barium azide

3 2 2Ba(N ) Ba 3N

2. In the laboratory dinitrogen is prepared by treating an aqueous solution of 4NH Cl with 2NaNO

4 (aq) 2(aq) 2(g) 2 (1) (aq)NH Cl NaNO N 2H O NaCl

3. Nitrogen can also be obtained by the thermal decomposition of ammonium dichromate

4 2 2 7 2 2 2 3(NH ) Cr O N 4H O Cr O


86. Give two reactions in which transition metals (or) their compounds acts as catalysis.

A. (1) 2 5V O is used as catalyst in manufacturing of 3SO from 2SO

2 5V O

2 g 2 g 3 g2SO O 2SO

(2) Fe is used as catalyst in manufacturing of 3NH

SFe

2 g 2 g f 3 gN 3H 2NH

87. A mixture of 3 2 Ca P and 2CaC is used in making Holme’s signal. Explain

A. A mixture of 3 2 Ca P and 2CaC is used in Holme’s signal. This mixture containing containers are pierced and

thrown in the sea, when the gas is evolved burn and serve as a signal. The spontaneous combustion of PH3 is the technical use of Holme’s signal.

88. Give one example each of normal oxide and mixed oxide of nitrogen.

A. Nitric oxide (NO) is an example of normal oxide of Nitrogen.

Dinitrogen trioxide ( 2 3N O ) is an example of mixed oxide of nitrogen.

89. Why 2H O is a liquid while 2H S a gas?

A. 2H O is liquid due to the presence of intermolecular hydrogen bonding. While 2H S is gas because it is not

having such type of bonding.

90. Nitrogen molecule is highly stable. Why?

A. Nitrogen molecule is more stable because in between two nitrogen atoms of N2, a triple bond is present.

To break this triple bond high energy is required (941.4KJ/mole).

91. Ammonia is a good complexing agent. Explain with an example.

A. NH3 is a Lewis base and it donates electron pair to form dative bond with metal ions. This results in the

formation of complex compound.

22(aq) 3(aq) 3 4 (aq)

Cu 4NH Cu(NH )

blue deep blue 92. Write the reactions of F2 and Cl2 with water.

A. Fluorine produces O2 and O3 on passing through water.

2 2 33F 3H O 6HF O

2 2 22F 2H O 4HF O

Chlorine dissolves in water giving a solution of chlorine water. A freshly prepared solution of chlorine water

contains HCl and HOCl .

2 2Cl H O HCl HOCl

HOCl is unstable and dissociates to give nascent oxygen.

HOCl HCl O

93. What is tailing of mercury. Explain?

A. Mercury loses it’s lustreness, meniscus and consequently sticks to the walls of glass vessel when it reacts

with ozone. This phenomenon is called tailing of mercury.

3 2 22Hg O Hg O O

It is removed by shaking it with water which dissolves Hg2O.

94. Which oxides of Nitrogen are neutral oxides?

A. Neutral oxides of 2N : 2N O , NO .


95. Draw the structure of 4 10P O .

Ans. Structure of 4 10P O

P

O

P

OP

O

P

O

O

O

O

O

OO

96. What is nitrolim? How is it formed?

A. Nitrolim: A mixture of calcium cyanamide and graphite is called nitrolim. 1000 C2 2 2

nitro limCaC N CaCN C

.

It is used to prepare 3NH by hydrolysis.


97. Give two examples each for amphoteric oxides and neutral oxides.

Ans. Examples of amphoteric oxides are Al2O3 and ZnO. Examples of neutral oxides are CO, NO and N2O.

98. Why is H2O a liquid while H2S is a gas?

Ans. The O – H bond in H2O is highly polar. There are hydrogen bonds among the molecules of H2O.

Hence it is present as a liquid.

There are no hydrogen bonds among H2S molecules. So it exists as a gas at room temperature.

99. Give the hybridisation of sulphur in the following

100. Explain the structures of SF4 and SF6


101.

102. List out the uses of neons

Ans. i) Neon is used in discharge tubes and fluorescent bulbs for advertisement display purposes.

ii) Neon bulbs are used in botanical gardens and In green houses.

103.

d & f BLOCK ELEMENTS AND COORDINATION COMPOUNDS


104. Scandium is transition element. But Zinc is not. Why?

A. Scandium has electronic configuration 2 1[Ar]4s 3d

Zinc has electronic configuration 2 10[ ]4 3Ar s d

Scandium has one unpaired d-electron where as Zinc has zero unpaired d-electrons so Scandium is transition element but Zinc is not.

105. What are complex compounds? Give examples.

A. Complex compounds: Transition metal atoms or ions form a large number of compounds in which anions or neutral groups are bound to metal atom or ion through co-ordinate covalent bonds. Such compounds are called co-ordination compounds (or) complex compounds.

Eg: 4 3

36 6Fe CN , Co NH


106. CuSO4.5H2O is blue in colour whereas anhydrous CuSO4 is colourless. Why?

A. CuSO4.5H2O is blue in colour whereas anhydrous CuSO4 is colourless because in the absence of ligand, crystal field splitting does not occurs.

107. Calculate the ‘spin only’ magnetic moment of 2(aq)Fe ion

A. 2Fe ion has electronic configuration 0 6[Ar]4s 3d

It has four unpaired electrons n = 4

Spin only magnetic moment n(n 2)BM 4(4 2) 24BM 4.9BM

108. Write the formulae for the following compounds.

a) Tetraamminecopper (II) Sulphate b) Potassiumtetrachloroplatinate (II).

A. a) Tetraamminecopper (II) Sulphate 3 44Cu NH SO

b) Potassiumtetrachloropalatinate (II) 2 4K PtCl

109. Write the systematic names of the following: a) 2K Ag CN b) 3 33Co NH Cl

A. 2K Ag CN -potassium dicyano Argentate (I) 3 33CO NH Cl -triamine trichloro cobalt (III).

110. Define effective Atomic Number. Calculate the EAN of Fe in 4 6K Fe CN .

A. EAN= Z O.N 2xC.N. i.e. total number of electrons present around central metal ion in a complex.

[O.N = Oxidation Number, C.N = Co-ordination Number]

for 4K , 6Fe CN .

EAN of Fe = 26 – 2 – 12 = 36

111. Calculate EAN of central metal ion in 3 24Co NH Cl

ion.

A. EAN of Co in 2

3 24Co NH Cl

= Z 0.N 2 CN 27 3 2 6 36 .

112. Write the systematic names for the following. a) 2 36Cr H O Cl b) 2 4K PtCl

A. 2 36Cr H O Cl - Hexaaquacobalt (III) chloride; 2 4K PtCl -potassiumtetrachloroplatinate (II).


113. Write the electronic configuration of chromium(Cr) and copper (Cu).

Ans. Cr 24) - 1s2 2s2

2p6 3s2

3p6 3d5

4s1 (or) [Ar]18 3d5 4s1

Cu (29) - 1s2 2s2

2p6 3s2

3p6 3d10

4s1 (or) [Ar]18 3d10 4s1

114. Why is Cr2+ reducing and Mn3+ oxidizing even though both have the same d4 electronic

configuration.

Ans. Cr2+ is reducing as its configuration changes from d4

to d3, the latter having a half-filled dxy, dyz, dzx orbitals. On the other hand, the change from Mn2+

to Mn3+ results in the half-filled d5 configuration which has extra

stability.

115. Why Zn2+ is diamagnetic whereas Mn2+ is paramagnetic?

Ans. Electronic configuration of Zn2+ is [Ar]3d10. As there are no unpaired electrons, Zn2+ is diamagnetic.

Electronic configuration of Mn2+ is [Ar]3d5. As there are unpaired electrons, Mn2+ is paramagnetic.

116. What is an alloy? Give example.

Ans. When metals are mixed and the resulting liquid is allowed to solidify, the product formed is called an alloy. It may also contain non-metals.

Ex. German silver 25 – 50% Cu,

10 – 30% Ni

25 – 35% Zn

Nichrome 60% Ni, 25% Fe, 15% Cr

Bell metal 80% Cu, 20% Sn


117. Aqueous Cu2+ ions are blue in colour, where as Aqueous Zn2+ ions are colourless. Why?

Ans. Cu2+ contains unpaired electron. It is coloured due to d – d transition. Zn2+ does not contain unpaired electron. Hence it is colourless.

118. Calculate the ‘spin only’ magnetic moment of 2(aq)Fe ion.

119. What is lanthanoid contraction?

Ans. Gradual decrease in atomic and ionic sizes from La to Lu is called Lanthanoid contraction.

Reason:

1) Imperfect shielding of one electron by another in the same set of orbitals (4f).

2) The shielding of one 4f electron by another is less than that of one d electron by another.

3) Nuclear charge increases along the series from La to Lu.

4) Due to poor shielding of 4f electrons, there is fairly regular decrease in the size of the entire 4f orbitals.

120. What is misch metal? Give its composition and uses.

Ans. Misch metal is an alloy of cerium.

Composition: Ce 50%, 25% L.a,15% M.o,10% other rare earths and iron (4-5%) and trace amounts of S, C, Ca and Al.

It is used in making tracer bullets.

121. What is a double salt? Give example.

122. What is a chelate ligand? Give example.

Ans. When a di- or polydentate ligand uses its two or more donor atoms to bind a single metal ion, is said to be a chelate ligand. It forms a cyclic ring around metal ion of complex. Ex: EDTA

( ethylenediaminetetraacetic acetate).

123. What is an ambidentate ligand? Give example.

Ans: Ligands, such as (NCS)–, that can bond to a central atom through either of two or more donor atoms are termed ambidentate.

124. [Cr(NH3)6]3+ paramagnetic while [Ni(CN)4]

2 – is colourless. Why?

125. [Fe(CN)4]

2 – and [Fe(H2O)6]2+ are of different colours in dilute solutions. Why?

126. What is the oxidation state of cobalt in (i) K[Co(CO)4] and (ii) [Co(NH3)6]

3+


POLYMERS


127. How are the polymers classified on the basis of structure?

A. On the basic of structure, polymers are classified into three types:

1) Linear polymers: These contains long and straight chains.

E.g.: PVC, polythene (high density) etc.

2) Branched chain polymers: These contains linear chains having some branches. E.g.: low density polythene.

3) Cross linked polymers (or) Network polymers: These are usually formed from bi functional and tri functional monomers an contain strong covalent bond between various linear polymer chains.

E.g: Bakelite, melamine etc..

128. Write the name and structure of one of the common initiators used in free radical polymerization reaction.

A. One of the common initiator used in free radial – polymerisation reaction is benzoyl peroxide.

Structure:

129. Is n[NH CHR CO] a homopolymer or a copolymer?

A. n[NH CHR CO] is a homopolymer. It is formed by the polymerisation of single monomer amino

acid 2(NH CHR COOH)

130. Give the structure of nylon 2-nylon -6

A. Nylon 2- Nylon 6:

It is an alternating polyamide copolymer of glycine

2

2

NH|CH COOH

and amino caproic acid 2 2 5(H N (CH ) COOH] . It is a biodegradable polymer.

Structure of Nylon 2-Nylon-6

2 2 5 nNH CH C NH CH C

|| ||O O

131. 3PCl can act as an oxidising as well as a reducing agent. Justify.

A. 3PCl acts as reducing agent. It is evidented by the following reaction.

3 2 53 5

PC Cl PCl

PCl3 acts as oxidising agent. It is evidented by the following reaction.

2H2 43 vapour

23

2PCl P Cl

132. What are thermosetting, thermo plastic polymers? Give examples.

A. Thermo setting polymers: These polymers are cross linked (or) heavily branched molecules which on heating undergo extensive cross linking in moulds and again become infusible.

E.g: Bakelite, urea – formaldehyde resin etc…..

Thermoplastic polymers: These are the linear (or) slightly branched long chain molecules capable of softening on heating and hardening or cooling. E.g: Polystyrene, polythene.


133. How can you differentiate between addition and condensation polymerisation?

A.

134. What are Copolymers? Give examples.

A. Copolymers: A polymer which is formed by the polymerisation of two (or) more chemically different types of

monomer units is called copolymer.

Ex: Butadiene – Styrene polymer (Buna-S)

135. What is PHBV? How is it useful to man?

A. Poly - hydroxy butyrate-CO- -hydroxy Valerate (PHBV): It is a copolymer of 3-hydroxy butanoic acid

and 3-hydroxy pentanoic acid.

Properties and uses: The properties of PHBV vary according to the ratio of both the acids, 3-hydroxy butanoic acid provides stiffness and 3-hydroxy pentanoic acid imparts flexibility to copolymer.

It is used in medicine for making capsules.

PHBV also undergoes degradation by bacteria.

136. Write the names and structures of the monomers of the following polymers.

a) Bakelite and b) Nylon 6,6

A. a) Bakelite:

Monomers:

Phenol, Formaldehyde

b) Nylon 6,6:

Monomers: Hexa methylene diamine

Adipic acid

137. What is Vulcanization of Rubber?

A. The process of heating the natural rubber with sulphur (or) sulphur compounds at 373-415 K to improve its properties is called vulcanisation of rubber.


138. What is PHBV? How is it useful to man?

A. PHBV is the poly -hydroxy butyrate-Co- -hydroxy-valerate.

It is a copolymer of 3-hydroxy butanoic acid and 3-hydroxy pentanoic acid.

Uses:

It is used in the field of medicine for making capsules

It is used in special packaging

It is used in orthopaedic devices

139. Give any two examples for Semi-synthetic Polymers.

A. Semi-synthetic polymers: Ex: cellulose nitrate, cellulose acetate i.e. rayon.

140. Write the names of monomers present in Terylene.

A. Terylene: it is a polymer made from monomers i) terepthalic acid ii) ethylene glycol.

CH2 CH2

OHOH+ COOHCOOH

COCO

O CH2 CH2 OHOH

n 141. Mention the names of the monomers used for preparing the following polymers.

a) Bakelite b) Nylon

A. Bakelite: A polymer of HCHO, Ph OH ; Nylon: A polymer of caprolactum

142. Mention the names of the monomers for preparing Bakelite and Teflon.

A. Polymers: Bakelite – Formaldehyde + phenol; Teflon – Tetrafluoro ethylene 2 2CF CF .


143. What are polymers? Give example.

Ans. Polymers are very large molecules having high molecular mass which are formed by linking together repeating units of small molecules called monomers.

Ex. Polythene

144. What is polymerisation? Give an example of polymerisation reaction.

Ans. The process of formation of a polymer from its monomer(s) is called polymerisation.

Ex :The formation of polythene from ethene.

145. What are homopolymers? Give example

Ans. Addition polymers formed by the polymerisation of a single monomeric species a re called homopolymers.

Ex: Polythene

146. What are copolymers? Give example

Ans. Polymers formed by addition polymerisation of two different monomeric species are called copolymers.

Ex :Buna - S.

147. What are elastomers? Give example.

Ans. Elastomers are rubber like solids with elastic properties. Ex :Buna - S.

148. What are fibres ? Give example.

Ans. Fibres are the thread forming solids which possess high tensile strength and high modulus. Ex :Terylene.

149. What is Ziegler- Natta catalyst ?

Ans. Trialkyl aluminium and titanium tetra chloride is called Ziegler- Natta catalyst.

Formula is 2 5 43Al C H TiCl

150. What is the difference between Buna-N and Buna-S .?

Ans. Buna-S obtained by the copolymerisation of 1, 3 -·butadiene and styrene whereas Buna- N is obtained by the copolymerisation of 1, 3 butadiene and acrylonitrile.


151. What is PDl (Poly Dispersity Index)?

Ans. The ratio between weight average molecular mass ( wM ) and number average molecular mass ( nM ) of a polymer is called Poly Dispersity Index (PDI).

152. What is biodegradable polymer ? Give one example of a biodegradable polyester?

Ans. Polymers which undergo environmental degradation are called biodegradable polymers.

Ex :Nylon 2 - nylon 6.

BIOMOLECULES


153. Write any one method of preparation of Glucose. Write the equation.

A. Preparation of glucose:

From Sucrose: Sucrose when boiled with dil.HCl in alcoholic solution then glucose, fructose are obtained in equal portions.

H12 22 11 2 6 12 6 6 12 6sucrose glucos e fructose

C H O H O C H O C H O

154. What is Peptide Linkage? Give an example.

A. Peptide linkage: It is amide linkage (O||C NH ) present in proteins formed from amino acids.


155. What are anomers ?

Ans. The two cyclic hemi acetal forms of glucose differ only in the configuration of the hydroxyl group at C-1 called anomeric carbon (the aldehyde carbon before cyclisation). Such isomers i.e., -form and -form are

called anomers.

156. What are amino acids? Give two examples.

Ans. Compounds containing both amino ( - NH2) and carboxyl ( - COOH) functional groups are called amino acids.

Ex. Glycine, Alanine.

157. What is Zwitter ion ? Give an example.

Ans. In an amino acid both acidic (carboxyl group) and basic (amino group) groups are present in the same molecule. In aqueous solution, the carboxyl group can lose a proton and amino group can accept a proton, giving rise to a dipolar ion known as Zwitter ion

Ex : H2N – CH2 – COOH Zwitter ion

2+H O

3 2H N - CH - COO

158. What are globular proteins ? Give examples.

Ans. Proteins in which the polypeptide chains coil around to give a spherical shape are called globular proteins.

Ex: Insulin

159. What are reducing sugars?

Ans. Carbohydrates which reduce Fehling's solution and Tollen's reagent are called reducing sugars.

160. What is glycogen? How is it different from starch ?

Ans. Carbohydrates are stored in animal body as glycogen. It is also known as animal starch. The structure of glycogen is similar to amylopectin, a component of starch, but it is more highly branched.

161. What are the hydrolysis products of i) sucrose and ii) lactose ?

Ans. i) Sucrose on hydrolysis gives D- (+)- glucose and D- (-)-fructose.

ii) Lactose on hydrolysis gives galactose and glucose.


162. What happens when D – glucose is treated with the following reagents.

i) HI ii) Bromine water iii) HNO3

Ans. i) On prolonged heating with HI, glucose forms n – hexane

ii) When glucose is treated with bromine water it gets oxidised to gluconic acid, a monocarboxylic acid with the molecular formula C6H12O7

iii) On oxidation with nitric acid, glucose gives a dicarboxylic acid called saccharic acid, with molecular formula, C6H10O8

3HNO4 4

2

Saccharic acid

CHO COOH

| |

CHOH CHOH

| |

CH OH COOH

163. Define the following as related to proteins.

i) Peptide linkage ii) Primary structure iii} Denaturation

Ans. i) Peptide linkage : Peptide linkage is an amide formed between -COOH group of one amino acid molecule and the NH2 group of another molecule of the same or different amino acid.

ii) Primary structure : The primary structure of proteins refers to the sequence of amino acids held together by peptide linkages.

iii) Denaturation :The loss of biological activity of a protein due to the destruction of the highly organized tertiary structure is called denaturation

164. What are the common types of secondary structure of proteins?

Ans. The secondary structure of proteins is of two common types :

1) - helix and

2) - pleated sheet structure

165. Differentiate between globular and fibrous proteins.

Ans. In globular proteins the polypeptide chains coil around to give a spherical shape. These are usually soluble in water.

In fibrous proteins the polypeptide chains run parallel and are held together by hydrogen and disulphide bonds. These proteins have a fibre - like structure. These are usually insoluble in water.

166. What are nucleic acids ? Mention their two important functions.

Ans. Nucleic acids are chains of five- membered ring sugars linked by phosphate groups. The anomeric carbon of each sugar is bonded to a nitrogen of a heterocyclic compound in a - glycosidic linkage.

Functions of nucleic acids :

1) DNA is the chemical basis of heredity and may be regarded as the reserve of genetic information.

2) Nucleic acids have an important role in protein synthesis. Actually the proteins are synthesised by various RNA molecules in the cell but the message for the synthesis of a particular protein is present in DNA


167. Write short notes on Sucrose

Ans. Sucrose (C12H22O11) is the most common disaccharide widely present in plants. It is mainly obtained from sugarcane or beetroot.

It is a colourless crystalline substance sweet to taste. It is dextrorotatory.

Sucrose on hydrolysis gives equimolar mixture of D- (+)-glucose and D - (-)-fructose. These two monosaccharide units are held together by a glycosidic linkage between C -1 of - glucose and C - 2 of - fructose. Since the reducing groups of glucose and fructose are involved in glycosidic bond formation, sucrose is a non - reducing sugar.

CHEMISTRY IN EVERYDAY LIFE


168. What is the difference between a soap and a synthetic detergent?

A. 1) Generally soaps are sodium or potassium salts of long chain fatty acids.

2) synthetic detergents are cleansing agents having all the properties of soaps and do not contain any soap

3) soaps do not work in hard water but synthetic detergents can be used both in soft and hard water as they

give foam even in hard water. Some of the detergents give foam even in ice cold water.

169. What are antacids? Give an example.

A. Antacids: Chemicals that remove the excess of acid in the stomach and maintain the pH to normal level are antacids.

Ex: Omeprazole.

170. Define Antibiotics. Give an example.

A. Antibiotics are chemical substances produced by microorganisms that inhibit the growth or destroy microorganisms.

Ex: Penicillins, chloramphenicol, sulphadiazine etc.

171. What are Antacids? Give an example.

A. Antacids: Chemicals that remove the excess acid in the stomach and maintain the pH to normal level are antacids.

Ex: Omeprazole, Lansoprozole etc.

172. Define Hormone. Given an example.

A. Hormone: Hormone is defined as an “Organic compound synthesised by the ductless glands of the body and carried by the blood stream to another part of the body for its function.”

Ex: Estradiol, Estrone etc.

173. Give two biological functions of Lipids.

A. Biological functions of lipids are as

1) Energy sources 2) Food reserves 3) structural Components of cell membrane

174. Give the deficiency diseases caused by A, D, E, K Vitamins.

Ans. S.NO. VITAMIN DEFICIENCY DISEASES 1 A Night blindness, Redness in eyes 2 D Rickets in children, osteomalacia in adults 3 E Sterility 4 K Blood coaqulation is prevented


175. What are Food preservatives? Give example.

A. Food preservatives: Chemical which are used to enhance the appeal and preservation of the food are called food preservatives.

Ex: sodium benzoate, salts of propionic and sorbic acids etc.

Anti oxidants are more reactive towards oxygen and retard the action of oxygen so preserve the food.

Ex: BHT, BHA, 2SO , etc.

176. Give the sources and deficiency diseases of vitamin E and K.

A. Sources of Vitamin E – wheat, egg yolk ; Vit K – Green vegetables. Deficiency diseases of Vitamin E – sterility; Vitamin K – Blood co-agulation is prevented.

177. What are Waxes? Give one example.

A. Waxes: Esters of long chain fatty acids with long chain monohydric alcohols. Ex. Bee’s wax.

178. What are lipids? Give one example.

A. Lipids: Esters of long chain fatty acids with alcohols. Soluble in organic solvents but insoluble in 2H O .

Ex. Fats, glycolipids, uses:energy sources, heat insulators.

179. What are vitamins? Give one example.

A. Vitamins: These are accessory factors which are essential for growth and healthy maintenance of body. Ex. Vit. A, Vit B-complex Vit C.

180. Define antiseptics. Give examples.

A. Antiseptics: These are chemical substances that kill or prevent the growth of microorganisms. Ex. Dettol, Bithioniol.

181. What are Hormones? Give two examples.

A. Harmones: Chemicals released into blood stream by ductless glands in body to perform specific metabolic actions. Ex: Estradiol, Estrone, Insulin.

182. Give the sources of vitamins A and C and diseases caused by their deficiency.

A. Vitamin A sources – Liver, fish oil, rice polishing deficiency diseases – Night blindness. Vitamin C source: citrous fruits, disease-scurvy.

183. What are artificial sweetening agents? Give an example.

A. Artificial sweetening agents: chemicals that cause sweetness with zero calorific value. Useful for diabetic patients. Ex. Sucralose, Aspartame.

184. What are analgesics? Give an example.

A. Analgesics: Pain reducers or pain abolishing chemicals. Ex. Morphine, aspirin, heroin.

185. Define Antihistamines. Give an example.

A. AntiHistamines: These are the chemicals which prevent the interaction of histamine with receptors present on stomach walls. Ex: Ranitidine, Cimetidine.


186. What are narcotic analgesics? Give example.

Ans. Morphine and many of its homologues when administered in medicinal dose relieve pain and produce sleep. These are called narcotic analgesics became they have additive properties.

Ex: heroin, Morphine and Codeine

187. What are non-narcotic analgesics? Give example.

Ans. Analgesics having no additive properties are called non-narcotic analgesics. These drugs have many other effects such as reducing fever and preventing platelet coagulation.

Eg. Aspirin.

188. What are antifertility drugs? Give example.

Ans. Drugs used to control population are called antifertility drugs.

Ex. Norethindrone, Ethynylestradiol (novestrol)

189. What is the difference between antiseptics and disinfectants?

Ans. Antiseptics are applied to living tissues such as wounds, cuts and diseased skin surfaces whereas disinfectants are applied to inanimate objects such as floors, drainage system, instruments etc…


ORGANIC CHEMISTRY


190. What are Enantiomers?

A. Enantiomers: The stereo isomers related to each other as non-superimposable mirror images are called enantiomers.

These have identical physical properties like melting point, boiling points, refractive index etc.

They differ in rotation of plane polarised light.

191. Which compound will react faster in SN2 reaction with – OH– ? CH3Br or CH3I.

A. CH3 – I reacts faster in SN2 - reaction with OH than CH3Br.

Reason: The bond dissociation enthalpy of C – I bond (234 KJ/mole) is less than that of C – Br bond

(293 KJ/mole).

192. Compare the acidic strength of acetic acid, chloro acetic acid, benzoic acid and phenol.

A. 6 56 5 2 3

C H OHC H COOH ClCH COOH CH COOHBenzoic acid Chloro acetic acid Acetic acid Phenol

193. How do you carry out the following conversion?

Aniline to p-Bromo aniline.

A. Conversion of Aniline to p – bromo aniline

194. Write the possible chain isomers of the compound having molecular formula C4H9Br

A. Compound having molecular formula C4H9Br has five isomers.

195. How is ethane converted to bromoethane?

A. Conversion of Ethane to Bromo Ethane.

sunlight3 3 2 3 2

Ethane BromoEthane

CH CH Br CH CH Br HBr

196. What is Reimer-Tiemann reaction? Give equation.

A. Reimer-Tiemann reaction: Chloroform in the presence of alkali reacts with phenol to form salicylaldehyde,

6 5 3 6 4 2C H OH CHCl 3NaOH C H OH CHO 3NaCl 3H O

Phenol Chloroform Salicylaldehyde

Salicylaldehyde is ortho hydroxyl benzaldehyde

CHO

OH

Salicylaldehyde


197. What is Williamson’s Synthesis? Give equation.

A. Ethyl chloride reacts with sodium ethoxide to form diethyl ether. This reaction is called Williamson synthesis.

2 5 2 5 2 5 2 5C H Cl NaOC H C H OC H NaCl

198. Write Hell Volhard Zelinsky (HVZ) reaction with equation.

A. When acetic acid is treated with chlorine in presence of red phosphorus mono, di and trichloro acetic acids are formed. This reaction is known as HVZ rection.

Cl

CH2COOH

Cl

CHCOOH

Cl

CCl3COOH

trichloro acetic acid

CH3COOHCl2 / red P

(-HCl)

Cl2 / red P Cl2 / red P

199. What is Carbylamine test (iso-cyanide test)? Give equation.

A. Carbylamine reaction: It is used to detect 1 amines. 3CHCl

OH1 Amine Isocyanide ( Bad smell)

2 3 2Ph NH CHCl KOH PhNC KCl H O ..

200. Explain the action of HI on Diethyl ether ( 2 5 2 5C H OC H ) in cold and hot conditions.

A. Action of HI on diethyl ether: HI2 5 2 5 2 5 2 5cold

C H OC H C H I C H OH HI2 5 2 5 2 5 2hot

C H OC H 2C H I H O

201. Complete the following reactions: a) 2 5NaOC H2 5C H Cl ............... b) Na, dry ether

2 5C H Cl ...............

A. Williamson synthesis: Alkyl Halide sod. alkoxide ether+sodium halide

Ex: NaCl2 5 2 5 2 5 2 5C H Cl C H ONa C H OC H

Wurtz reaction: Naether

alkyl halide alkane , ether2 5 2 5 4 10NaCl

C H Cl 2Na Cl C H C H

(n-butane).

202. How Aspirin is prepared? Give equation.

A. Aspirin: It is antipyretic (Acetyl Salicyclic Acid).

COOH

OH

+ AC2O-CH3COH

COOH

O C

O

CH3

Salicylic acid Aspirin 203. Mention the Reimer-Tiemann reaction with an equation.

A. Reimer – Tiemann reaction: Reaction of phenol with 3CHCl KOH to form salicylaldehyde

OH

+ CHCl3 + KOH CHO

OH+ NaCl +H2O

204. Complete the following statements: a) 4LiAlH3CH COOH b) 4 10P O

3CH COOH

A. (a) 4LiAlH3 3 2

E t hanol

CH COOH CH CH OH (b) 4 10

O O

P O3 3 3

|| ||

Acetic anhydride

2CH COOH CH C O C CH


205. Write the structures of the following compounds.

(i) 2-chloro-3-methylpentane (ii) 1-Bromo-4-sec-butyl-2-methylbenzene

Ans.

CH3 CH3

HHH

H CH3 Cl

CH3 C C

H

H H

CH3

Br

CH3

2 chloro 3 Methyl pentane 1 Bromo 4 sec butyl 2 methyl benzene


206. What are ambident nucleophiles?

Ans. The groups which contain two nucleophilic centres are called ambident nucleophiles.

E.g: cyanide group Θ ΘC N : C N

Cyanide group has two nucleophilic centres carbon and nitrogen

E.g: Nitrate ion ΘO N O

..

The linkage through oxygen form alkyl nitrites while through nitrogen atom form nitro alkanes.

207. Which compound in each of the following pairs will react faster in SN2 reaction with OH?

(i) 3CH Br or 3CH I (ii) 3 3CH CCl or 3CH Cl

Ans. (i) 3CH I reacts faster than 3CH Br

C I bond break easily than C Br bond

(ii) 3CH Cl reacts faster than 3 3CH CCl

Primary alkyl halides reacts faster than tertiary alkyl halide. As bulkiness increases rate of reactivity of alkyl halide in 2SN reaction decreases.

208. Explain why the alkyl halides though polar are immiscible with water.

Ans. Alkyl halides cannot form H-bonds with water. The molecular interactions between alkyl halides and water molecules are very weak compared to the molecular interactions either between alkyl halide molecules (or) water molecules. So alkyl halides immiscible with (slightly soluble) water.

208. Out of C6H5CH2Cl and C6H5CHClC6H5, which is more easily hydrolysed by aqueous KOH?

Ans.

209. Give the structures and IUPAC names of monohydric phenols of molecular formula, C7H8O.

Ans. Three monohydric phenols are possible for the molecular formula 7 8C H O

210. What type of isomerism is exhibited by ortho, meta and para chloro benzenes?

Ans. Positional isomerism is exhibited ortho, meta and para chloro benzenes.

Ortho, meta and para chloro benzenes are positional isomers

Cl

Cl

Cl

Cl

Cl

Cl

o-isomer m-isomer p-isomer

211. Treatement of alkyl halide with aq.koH leads to formation of alcohols, while in presence of alc.koH. What are formed?

Ans. Treatment of alkyl halides with alc.kOH produce alkenes by dehydrohalogenation process while aq.kOH produce a substitution product i.e., alcohol. In reactions, aq.kOH acts as strong nucleophile while alc.koH acts as strong base.


212. Write the mechanism of the reaction of HI with methoxymethane.

Ans. The reaction of ether with concentrated HI follows 2SN mechanism.

It proceeds in three steps

Step-1: Protonation of ether molecule

Step-2: Nucleophile attacks least substituted carbon of oxonium ion formed in step-1

Step-3: When HI is in excess and the reaction is carned out at high temperature. Alcohol react with another molecule of HI and is concentrated to alkyl iodide.

213.

214. Write the equations for the following reactions.

(i) Oxidation of primary alcohol to carboxylic acid

(ii) Benzyl alcohol to benzoic acid

Ans.

215. Write the structures for the following compounds

(i) Ethoxyethane (ii) Ethoxybutane (iii) Phenoxyethane

Ans. (i) 2 5 2 5C H O C H (ii) 2 5 2 2 2 3C H O CH CH CH CH (iii) 6 5 2 5C H O C H

216. How do you distinguish acetophenone and benzophenone?

Ans. Acetophenone Benzophenone

(1) It gives haloform test (1) It does not give haloform test

(2) It gives aldol condensation (2) It does not give aldol condensation

(3) It does not give cannizaro reaction (3) It gives cannizaro reaction


SHORT ANSWER QUESTIONS

SOLID STATE

1. Derive Bragg’s equation.

2. Explain Schottky defect and frenkel defect in Solids?

SOLUTIONS

3. (a) State Raoult’s law

(b) Calculate the Vapour Pressure of the solution at 293 K when 25 grams of glucose is dissolved in 450 grams of Water.

4. (a) What is meant by positive deviation from Raoult’s law and how is the sign of mixH related to positive

deviation from Raoult’s law?

(b) Calculate the molarity of solution containing 5 g NaOH in 450 solution.

5. What is meant by negative deviation from Raoult’s law and how is the sign of mixH related to negative

deviation from Raoult’s law?

6. What is relative lowering of Vapour Pressure? Calculate the mass of a non-volatile solute (molar mass 40gram.mol–1) which should be dissolved in 114 gram octane to reduce its vapour pressure to 80%?

7. (a) What is ideal solution?

(b) Calculate the mole fraction of H2SO4 in a solution containing 98% H2SO4 by mass?

8. (a) What is molality, molarity, molefraction of solution?

(b) Calculate the molarity of a solution containing 5 grams of NaOH in 450 mL solution?

9. A solution of sucrose in water is labelled as 20% w/w. What would be the mole fraction of each component in the solution.

10. What is relative lowering of vapour pressure? How is it useful to determine the molar mass of solute?

ELECTRO CHEMISTRY

11. (a) State and Explain Nernest equation with the help of a metallic electrode and a non-metallic electrode?

(b) Calculate the equilibrium constant of the reaction 2Cu S 2Ag aq Cu aq 2Ag s .

12. (a) Give the construction and working of a standard hydrogen electrode with a neat diagram.

(b) The standard emf of Danlell cell is 1.1 V. Calculate the standard Gibbs energy for the cell reaction

2 2Zn s Cu aq Zn aq Cu s

13. What is metallic corrosion? Explain it with respect to iron corrosion.

SURFACE CHEMISTRY

14. Give any four differences between Physisorption and Chemisorption.

15. What is Catalysis? How it is classified? Give two examples for each type of Catalysis?

16. What are lyophilic and lyophobic sols? Compare the two terms in terms of stability and reversibility?

17. (a) What is emulsion? How are they classified? (b) Name two emulsifiers.

18. (a) Define Gold number. (b) Explain formation of micelle.

CHEMICAL KINETICS

19. Derive integrated rate equation for zero order reaction?

20. Derive integrated rate equation for first order reaction?

21. A reaction has a half-life of 10 minutes. Calculate the rate constant for the first order reaction.

22. Define and explain the order of a reaction. Calculate the half life of first order reaction whose rate constant

is 1200s ?

METALLURGY

23. Define Calcination and Roasting. Give one example of each?

24. Explain the purification of Sulphide ores by froth flotation method?

25. Explain following methods.

(a) Zone refining (b) Electrolytic refining (c) poling (d) vapour phase refining

26. Explain the process of extraction Aluminium from bauxite?


27. Explain the extraction of Zinc from zinc blende.

28. Explain the purpose of Vulcanization of rubber.

29. Write any two ores with formula of the following metals?

(a) Aluminium (b) Zinc (c) Iron (d) Copper

30. Give two uses of each of the following metals

(a) Zinc (b) Copper (c) Iron (d) Aluminium

p-BLOCK ELEMENTS

31. How is chlorine obtained in the laboratory? How does it react with the following?

(a) Cold. dil NaOH (b) excess 3NH (c) KI

32. Write the names and formulae of the oxo acids of chlorine

d-BLOCK, f-BLOCK AND CO-ORDINATION COMPOUNDS

33. Explain Werner’s theory of co-ordination compounds with suitable examples?

34. Using IUPAC norms write the formulas for the following

(a) Tetrahydroxo zincate (II) (b) Hexaammine cobalt (III) sulphate

(c) Potassium tetra chloropalladate (II) (d) Potassium tri(oxlato) chromate (III)

(e) Tetra Carboxylnickel (O)

35. Using IUPAC norms write the systematic names of the following

(a) [Co(NH3)6]Cl3 (b) [Ti(H2O)6)+3 (c) [NiCl4]

2– (d) [Pt(NH3)2Cl(NH2CH3)]Cl

36. What is lanthanide contraction? What are the consequences of lanthanide contraction?

37. Discuss the nature of bonding and magnetic behaviour in the following co-ordination entities on the basis of valence bond theory?

(a) 4

6Fe CN (b) 36FeF

(c)

3

2 4 3Co C O

(d) 36CoF

38. What are interstitial compounds? How are they formed? Give two examples?

POLYMERS

39. (a) What are additional polymers? Give example? (b) What is PHBV? How it is useful to man?

40. Explain (i) additional polymerization (ii) condensation polymerization

41. What are synthetic rubbers and explain the preparation and uses of the following:

(i) neoprene (ii) buna-N (iii) buna-S

42. What are LDP and HDP and how they are formed?

43. Explain co-polymerisation with an example?

44. What is Zeigler-Natta catalyst?

BIOMOLECULES

45. Give the sources of the following vitamins and name the diseases caused by their deficiency.

(a) A (b) D (c) E (d) K

46. What are hormones? Give one example of each?

(A) steroid hormones (B) polypeptide hormones (C) amino acid derivatives

47. Explain denaturation of proteins?

48. Explain structures of RNA and DNA?

CHEMISTRY IN EVERY DAY LIFE

49. Write short notes on (i) analgesics (ii) food preservatives

50. Write notes on antiseptics and disinfectants?

51. What are artificial sweetening agents and food preservatives and give one example of each?

52. Explain the cleaning action of soap.

ORGANIC CHEMISTRY

53. (i) Explain sandmeyer reaction (ii) carbylamine reaction

54. Explain 1SN and 2SN reactions?


55. Compare the basicity of the following in gaseous and in aqueous state and arrange them in increasing order of basicity?

3 2 3 32 3CH NH , CH NH, CH N and 3NH

56. Give structures of A, B and C in the following reaction.

32 NH ,H O HCuCN6 5 2C H N Cl A B C

57. Arrange the following in the increasing order of their acidic strength.

Benzoic acid, 4-methoxy benzoic acid, 4-nitrobenzoic acid and 4-methylbenzoic acid

58. Write the IUPAC name of the following compounds.

CH3

OH

CH3

OH

CH3

OH

CH3

CH3

OH

CH3

(A) (B) (C) (D)

59. Ethanol with 2 4H SO at 443 K forms ethane while at 413K it forms ethoxy ethane. Explain the mechanism?

60. Write the products of the following

(A)

OC2H5HBr

(B)

OC2H5 Conc. H2SO4

Conc. HNO3

61. In the following pairs of halogen compounds, which compound undergoes faster in 1SN reactions.

(i)

Cl

and

Cl

(ii)

Cl

and Cl

62. Predict the alkenes that would be formed in the following reactions and identify the major alkene

(i)

Br CH3

NaOEt

EtOH

(ii) NaOEtEtOH

2-chloro-2-methylbutane

63. Explain why the dipole moment of chlorobenzene is lower than that of cyclohexyl chloride?

LONG ANSWER QUESTIONS

ELECTRO CHEMISTRY

1. (a) State and Explain Kohlrausch’s law of Independent migration of icons and its applications?

(b) What are fuel cells? How are they different from galvanic cells? Give the construction of H2, O2 fuel cells?

2. (a) What is electrolysis?

(b) State faraday’s first and second law of electrolysis?

(c) A solution of CuSO4 is electrolyzed for 10 minutes with a current of 1.5 amperes. What is the mass of Copper deposited at the Cathode.

3. What are electrochemical cells? How are they constructed? Explain the working of the different types of galvanic cells?


CHEMICAL KINETICS

4. (a) What is Arrhenius equation? Derive the equations for the half life value of zero and first order reaction?

(b) A first order reaction is found to have a rate constant 14 1k 5.5 10 s . Find the half life of the reaction?

5. (a) What is order of reaction and molecularly of the reaction.

(b) How order of reaction is different from the molecularity of a reaction. Give examples of first order and second order reactions.

6. (a) Describe salient features of the collision theory of reaction rates of bimolecular reactions.

(b) Explain the effect of temperature and catalyst on the rate of reaction.

(c) Name one bimolecular and one tri molecular gaseous reaction.

p-BLOCK ELEMENTS

7. (a) How is ammonia manufactured by Haber’s process with a neat diagram

(b) Explain the reaction of ammonia with

(a) ZnSO4 (b) CuSO4 (c) AgCl (d) FeCl3

8. How is nitric acid manufactured by ostwald’s process? How does it react with following?

(a) Copper (b) Zn (c) 8S (d) 4P

9. Explain in detail the manufacture of sulphuric acid by contact process?

10. (a) How is Ozone prepared from oxygen?

(b) Explain its reaction with (i) C2H4 (ii) KI (iii) Hg (iv) Pbs (v) Ag

11. (a) How is chlorine prepared in the laboratory by deacon’s method?

(b) How does it react with the following

(a) Iron (b) Iodine (c) H2S (d) Na2SO3 (e) hot conc NaOH (f) acidified FeSO4

12. (a) How is chlorine prepared by electrolytic method?

(b) Explain its reaction with (a) NaOH (b) NH3 under different conditions

13. (a) Explain structure of XeF4, XeF6 and XeOF4

(b) How are Xenon fluorides XeF2, XeF4 and XeF6 obtained

ORGANIC CHEMISTRY

14. (a) Explain

(i) Cannizaro reaction (ii) Decarboxylation (iii) Aldol condensation (iv) Cross aldol condensation

(b) Explain the acidic nature of phenols and compare it with that of alcohols.

15. Explain the following with one example.

(i) Esterification (ii) Swart reaction (iii) Hell volhard – Zelinsky reaction

(iv) Aldol condensation (v) Diazotization (vi) Williamson’s synthesis

16. Explain the following with one example

(a) Reimer – Tiermann reaction (b) Kolbe’s reaction (c) Wurtz fitting reaction (d) fitting reaction

17. Explain the following with one example

(a) esterification reaction (b) Williamson synthesis

(c) Hoff mann bromamide degradation (d) Gabriel Pthalamide synthesis (e) Gatterman reaction

18. Write any two methods of preparation of Phenol. Give their corresponding equations.

19. (a) Explain the preparation of ethyl alcohol from molasses?

(b) How does ethylalcohol react with the following? Write equations.

(i) Matallic Na (ii) CH3COOH (iii) CH3MgI (iv) Conc.H2SO4 at 1700 C

20. (a) Explain SN1 and SN2 reactions with mechanism?

(b) What happens when n-butyl chloride is treated with alc.kOH

(c) What happens when bromo benzene is treated with Mg in presence of dry ether.

21. Explain the following conventions

(1) Propene to propanol (2) Ethanol to but-1-yne

(3) 1-Bromopropane to 2-Bromo propane (4) Aniline to chloro bezene

(5) Benzyl chloride to Benzyl alcohol (6) Ethyl magnesium bromide to propanol

(7) 2-butanone to 2-butanol (8) Acetic acid to acetyl chloride

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