Solutions

Question 1

V.P of pure water =

Answer 1

1.013 bar

Question 2

Rate constant depends on

Answer 2

Temp

Question 3

Henry’s law

Answer 3

Pressure of gas above the sol is directly proportional to mole fraction of gas inside the sol.

Question 4

Pressure depends on

Answer 4

Nature of solute, temp, nature of solvent

Question 5

Application of Henry’s law

Answer 5

1. Preparation of soda water
2. Oxygen cylinders by scuba divers which are compressed & diluted with He
3. Used in high altitude to prevent anoxia

Question 6

Vapour pressure of a liquid

Answer 6

Pressure exerted by vapours of liquid at eq.

Question 7

Factors affecting vapour pressure

Answer 7

1. Nature of liquid: If intermolecular forces are strong, V.P is less
2. Temp: directly prop

Question 8

Raoult’s law

Answer 8

In liquid-liquid sol, partial pressure exerted by one component is directly prop to its mole fraction in sol

Question 9

Effect of adding non-volatile solute to volatile solvent

Answer 9

VP decreases. So pressure exerted above the sol. is prop only to mole fraction of solvent

Question 10

Ideal sols

Answer 10

That obey Raoult’s law

Question 11

Ideal sols examples

Answer 11

n-hexane & n-heptane, benzene & toluene, chloroethane & bromoethane

Question 12

For +ve deviation, P >

Answer 12

P`X

Question 13

For +ve deviation, process is

Answer 13

endothermic

Question 14

In endothermic process, ΔH(mix) & ΔV(mix) is

Answer 14

+ve

Question 15

For ideal solns, ΔH & ΔV is

Answer 15

0

Question 16

+ve deviation examples

Answer 16

ethyl alcohols & acetone, carbondisulphide & acetone, ethyl alcohol & water

Question 17

-ve deviation examples

Answer 17

Nitric acid & water, CCl4 & acetone, Phenol & aniline

Question 18

When intermolecular H bond is less, solns show ____ deviations

Answer 18

+ve

Question 19

Azeotropic mixture

Answer 19

Mixture in which components have a definite BP & has the same composition in liquid & VP

Question 20

Min boiling azeotropic mixture

Answer 20

Mixture in which BP of mixture is less than BP of individual components

Question 21

Min boiling azeotropic mixtures show _______ deviation

Answer 21

+ve

Question 22

Examples of Min boiling azeotropic mixture

Answer 22

Ethanol & water

Question 23

Examples of max boiling azeotropic mixture

Answer 23

HNO3 & water

Question 24

Colligative properties

Answer 24

Those properties which depends on amount of solute & not its nature

Question 25

K(b) is called

Answer 25

molal elevation/Ebullioscopic const

Question 26

K(f) is called

Answer 26

molal depression/Cryoscopic const

Question 27

Applications of depression in freezing point

Answer 27

1. In cold countries, to avoid freezing of water in radiators of cars, ethylene glycol is added
2. To remove snow blocks on roads, it is sprinkled with NaCl

Question 28

Osmotic pressure

Answer 28

Min excess pressure to be applied on sol. to stop osmosis

Question 29

Desalination of sea water

Answer 29

Applied pressure is more than osmotic pressure to extract salt from sea water

Question 30

Osmosis

Answer 30

Movement of solvent from higher to lower conc. via semi-permeable membrane

Question 31

Osmotic pressure is applicable only to

Answer 31

dilute solutions

Question 32

Use of osmotic pressure

Answer 32

1. Calculate MM of macro molecules like proteins & polymers

Question 33

Advantage of osmotic pressure

Answer 33

It is done at room temp & molarity is used instead of molality

Question 34

Polymers have ______ solubility

Answer 34

less

Question 35

Isotonic solns.

Answer 35

Solns. with same osmotic pressure

Question 36

hypertonic solns.

Answer 36

Soln. having more osmotic pressure than another

Question 37

Osmosis doesn’t take place for

Answer 37

isotonic solns.

Question 38

When is MM abnormal?

Answer 38

When solute of electrolyte undergoes associaton or dissociation which increases or decreases no. of particles

Question 39

Van’t Hoff factor increases when

Answer 39

Conc decreases or no. of ions increases

Question 40

Why is decrease in temp of ethanol & acetone observed?

Answer 40

They form a non-ideal sol with +ve deviation which increases vol

Question 41

When does a sol freeze?

Answer 41

When its vapour pressure equals the vapour pressure of pure solid solvent.

Question 42

-ve deviation ___________ temp

Answer 42

increases

Question 43

λ(m) increases rapidly for

Answer 43

weak electrolytes

Question 44

Lowering of V.P _____________ B.P

Answer 44

increases

Question 45

Define fuel cell

Answer 45

A fuel cell is an electrochemical cell that generates electrical energy from fuel via an electrochemical reaction

Question 46

Why is it not possible to obtain pure ethanol by fractional distillation?

Answer 46

Due to const composition so it forms an azeotrope

Question 47

What general name is given to binary mixtures which show deviation from Raoult’s law

Answer 47

Azeotropes

Question 48

If BP is higher than that of the 2 liquids, it shows

Answer 48

large -ve deviation from Raoult’s law

Question 49

If rn is endothermic, when temp increases solubility

Answer 49

Increases

Question 50

Factors affecting solubility

Answer 50

Stronger intermolecular forces, more soluble in water
Temp increases, it decrease if rn is exothermic
Pressure more solubility more