1 MARK QUESTIONS

1.What is vant Hoff’s factor for a compound which undergoes dimerisation in an organic solvent? [E-U]
2.State Raoult’s law for a solution of volatile liquids. [E-U]
3.What are isotonic solutions? [E-C]
4.Two liquids X and Y boil at 1100C and 1300C respectively. Which one of the following has higher vapour
pressure at 500C? [E-C]
5.What happens when blood cells are placed in pure water? [E-U]
6.What is vant Hoff’s factor for a compound which undergoes tetramerisation in an organic solvent? [E-U]
7. 10 cm3 of a liquid A was mixed with 10 cm3 of liquid B. The volume of the resulting solution was found to
be 19.9 cm3. What do you conclude ? [E-C]
8. Define boiling point elevation constant for a solvent. [E-C]
9. State the main advantage of molarity over molality as the unit of concentration. [E-U]
10. Why vapour pressure of a solution of glucose in water lower than that of water? [E-U]
11. State Raoult’s law for a solution of volatile liquids. [E-U]
12. What are azeotropes? [E-C]
13.What is meant by molality of the solution? [E-C]
14.State the advantage of molarity over molality as the unit of concentration. [E-C]
15.Define ideal solution. [E-C]
16.Define the term osmotic pressure. [E-C]
17.Define Ebullioscopic constant. [E-C]
18.Define Cryoscopic constant. [E-C]
19.What is reverse osmosis? E-C[]
20.What is the condition for reverse osmosis? [E-U]
21.Define colligative properties. [E-C]

2 MARKS QUESTIONS

1. Calculate the mass percentage of benzene (C6H6) and carbon tetrachloride (CCl4) if 22 g of benzene is
Dissolved in 122 g of carbon tetrachloride. [avg-A]
2.(a) What is van’t Hoff factor for NaCl in aqueous solution? [E-U]
(b) How much molecular mass of KCl is obtained experimentally using colligative property? [E-U]
3.Define the term osmotic pressure and reverse osmosis. What is the advantage of using osmotic
pressure as compared to other colligative properties for the determination of molar masses of solutes
in solution. [E-U]
4. State the law co-relating the pressure of a gas and its solubility in a liquid. Mention two
applications of this law. [E-U]
5. State the law co-relating the pressure of a gas and its solubility in a liquid. Mention two applications of
this law. [E-U]
6.(a)Between 1M BaCl2 & 1M FeCl3 which has higher boiling point & why? [E-MD]
(b)Arrange the following in order of increasing solubility in n-hexane.
Cyclohexane, KCl, CH3OH, CH3CN
7. Define the following terms: [E-C]
(i) isotonic solutions
(ii) van’t Hoff factor
8.State Henry s law and write its application. [E-C]
9.A solution of glucose in water is labbled as 10% by mass.What would be the molarity of the
solution. E-A[]
10.Find the boiling point of a solution containing 0.52g of glucose dissolved in 80.2g of water.[K b = 0.52
K m-1]. [E-A]

11. Find the freezing point of a solution containing 0.52g of glucose dissolved in 80.2g of water.[K f = 1.86
K m-1]. [E-A]
12.The molecular masses of polymers are determined by osmotic pressure method and not by
measuring other colligative properties. Give two reasons. [E-U]

3 MARKS QUESTIONS

1. On dissolving 19.5 g of CH2FCOOH in 500 g of water, a depression of 10 C in freezing point

Of water is observed. Calculate the vant Hoff factor and dissociation constant of fluoroacetic
acid.Given, Kf =1.86 K kg mol-1. [avg-A]
2.A solution containing 2.56g of sulphur dissolved in 100g of naphthalene whose melting point
is 80.1oc gave a freezing point lowering of 0.680oc. Calculate the formula of sulphur. (Kf for
naphthalene = 6.8K/m). [E-A]
3.Calculate the freezing point of an aqueous solution containing 10.5g of MgBr2 in 200g of
water. Given molar mass of MgBr2 =184 g/mol and Kf for water=1.86 k.kgmol-1. [avg-A]
4.Non-ideal solutions exhibit either positive or negative deviations from Raoult’s law. What are
these deviation and how they caused? Explain with example. [E-U]
5.A solution is prepared by dissolving 5 g of non-volatile solute in 95 g of water. It has a vapour
pressure of 23.375 mm of Hg at 250 C. Calculate the molar mass of the solute.(Vapour pressure
of pure water at 250C is 23.75 mm of Hg) [avg-A]
6.(i) What is meant by colligative properties? [E-MD]
(ii)Calculate the mass of ascorbic acid C6H8O6 to be dissolved in 75g of acetic acid to lower
Its melting point by 1.5oC. [given Kf for acetic acid is 3.9K kg mol-1].
7.(i)Define the term azeotropes. [E-U]
(ii)Diagrammatically represent the solution showing positive and negative deviation from Raoult's law.
8. Calculate the freezing point of an aqueous solution containing 10.5g of MgBr 2 in 200g of water. Given
molar mass of MgBr2 =184 g/mol and K7 for water=1.86 k.kgmol-1. [E-A]
10. Non-ideal solutions exhibit either positive or negative deviations from Raoult’s law. What are these
deviation and how they caused? Explain with example. [E-U]
11. State Raoult’s law for solutions of volatile liquid components. Taking a suitable example, explain the
meaning of positive deviation from Raoult’s law. E-U[]
12. Calculate the boiling point of a solution prepared by adding 15g of NaCl to 250 g of water. Given molar
mass of NaCl= 58.5 g/mol-1 & Kb for water = 0.512 k. kg mol-1. [E-A]

13. Define the terms osmosis and osmotic pressure. What is the advantage of using Osmotic pressure as
compared to other colligative properties for the determination of molar masses of solutes in solution? [E-U]

14.Phenol forms dimer in benzene. A solution containing 20g phenol in 1kg benzene has its freezing point
decreased by 0.69K.Calculate the fraction of phenol that has dimerised.(K f=5.1Kkg/mol) [E-A]

15.(a)Why is freezing point depression of 0.1M NaCl solution nearly twice that of 0.1M
glucose solution? [E-MD]
(b)What is reserve osmosis? Write down one of its application.
16. Calculate the boiling point of one molar aqueous solution. Density of KBr solution is 1.06 g mL -1.(Kb for
H2O = 0.52 K kg mol-1,Atomic mass; K= 39, Br= 80.) [E-A]
17. Define the terms osmosis and osmotic pressure. What is the advantage of using osmotic pressure as
compared to other colligative properties for the determination of molar masses of solutes in
solutions? [E-U]
 5 MARKS QUESTIONS

1.(i)Define Van’t Hoff’s factor.What possible values will it have if the solute molecules undergo
association?. [E-MD]
(ii)Determine the amount of CaCl2(i=2.47)dissolved in 2.5litre of water such that its osmotic pressure is
0.75atm at 270C.

2. (i)Define azeotropes and explain briefly minimum boiling azeotropes by taking suitable example ? [E-MD]
(ii)A 5% solution (by mass ) of cane sugar in water has freezing point of 271K.Calculate the freezing
point of a 5% glucose in water if the freezing point of pure water is 273.15K.
3.(i)State Raoult’s Law for solution of volatile components. Taking a suitable example explain the
meaning of positive deviation from Raoult’s Law? [E-MD]
(ii)A solution containing 16gms of a substance in 200gms of diethyl ether boils at 36.86 0C whereas
pure ether boils at 35.5oC .Determine the molecular mass of solute.
(Given Kb for ether=2.02Kkg/mol)
4.(i)Define the term Osmotic pressure. Describe how the molecular mass of the substance can be
determined on the basis of Osmotic pressure measurement. [avg-MD]
(ii)Calculate the temperature at which a solution containing 54gms of glucose,C 6H12O6 in 250gms of
water will freeze.[Kf for water= 1.86K kg/mol, freezing point of water=273.15K].
5. (i) Why is freezing point depression of 0.1 M NaCl solution nearly twice that of 0.1 M glucose
solution? Avg-MD[]
(ii) Solution of chloroform and acetone is an example of maximum boiling azetrope. Explain.
(iii) Calculate boiling point of a solution contaiing 0.61 g of benzoic acid in 5 g of . Assuming 84%
dimerisation of acid. The boiling point and of . Are 46.2o and 2.3 k. kg. respectively.
6.(i) Describe how the molecular mass of a substance can be determined by a method based on
measurement of osmotic pressure. [E-MD]
(ii) A doctor advised a person suffering from high blood pressure to take less quantity of common salt.
Explain.
(iii) What mass of ethylene glycol (molar mass = 62 g/mol) must be added to 5.5 kg of water to lower the
freezing point of water from to ? ( for water = 1.86 k.kg )
7. (i)Define the term osmotic pressure. [E-MD]
Describe how the molecular mass of a substance can be determined on the basis of osmotic
pressure measurement.

(ii)The osmotic pressure of a 0.0103 molar solution of an electrolyte is found to be 0.7 atm at 27`c.
Calculate Van’t of factor(R=0.082 L.atm mol K-1.

8.(a) Define the following terms: E-MD[]

(i)Isotonic solutions
(ii)Van’t Hoff factor
(b)A solution containing 15 g urea (molar mass = 60 g mol-1) per litre of solution in water has the same
osmotic pressure(isotonic) as a solution of glucose (molar mass = 180 g mol-1) in water. Calculate
the mass of glucose present in one litre of its solution.
9. (a) Define the following terms. [E-MD]

(i) Ideal solution (ii) Azeotropes

(b)Calculate the molarity and molality of a 15% solution by weight of H2SO4 of density 1.02g\cm3.

10.(a)Define the following terms. E-MD[]

(i) Mole fraction (ii) Van’t Hoff factor.
(b)How much urea(mol mass=60g/mol) should be dissolved in 50 g of water so that its vapour pressure
at room temp is reduced by 25% ? calculate molality of the solution obtained.
11. (i) Define the term osmotic pressure. [E-MD]
(ii)Describe how the molecular mass of a substance can be determined on the basis of osmotic
pressure measurement.
(iii)The osmotic pressure of a 0.0103 molar solution of an electrolyte is found to be 0.7 atm at 27 0C.
Calculate Van’t of factor(R=0.082 L.atm mol K.

12. (a) Differentiate between molality and morality of a solution. What is the effect of change in
temperature of its molality and molarity values. [E-MD]

(b) The vapour pressure of pure water at 373k is 760 mm Hg while that of a dilute aqueous solutios of
glucose is 750 mm Hg at the same temperature. Calculate mole fraction of solute and molality of the
solution.

13. Derive an equation to express that relative lowering of vapour pressure of a solution s equal to mole
fraction of the solute in it when the solvent alone is volatile. [avg-MD]
(b) On dissolving 3.24g of sulphur in 40g of benzene boiling point of solution was higher than that of
benezene by 0.81 K. Kb value for beneze is 2.53k.kg mol-1. What is the molecular formula of sulphur.
14. (a) Define the following terms. [avg-MD]
(i)Isotonic solutions (ii) Colligative properties
(b) A solution prepared by dissolving 8.95mg of a gene fragment in 35ml of water has an osmotic pressure of
0.335 toor at 250c. Calculate the molar mass of gene fragment.
15. .(i)State Raoult’s Law for solution of volatile components. Taking a suitable example explain the
meaning of positive deviation from Raoult’s Law? [E-MD]
(ii)A solution containing 16gms of a substance in 200gms of diethyl ether boils at 36.86 0C whereas
pure ether boils at 35.5oC .Determine the molecular mass of solute.(Given Kb for ether =2.02Kkg/mol).
16. (i)Define the term Osmotic pressure. Describe how the molecular mass of the substance can be
determined on the basis of Osmotic pressure measurement. [E-MD]
(ii)Calculate the temperature at which a solution containing 54gms of glucose, C6H12O6 in 250gms of
water will freeze.[Kf for water= 1.86K kg/mol, freezing point of water=273.15K].
17. (i) Why is freezing point depression of 0.1 M NaCl solution nearly twice that of 0.1 M glucose solution? [E-MD]
(ii) Solution of chloroform and acetone is an example of maximum boiling azetrope. Explain.
(iii) Calculate boiling point of a solution contaiing 0.61 g of benzoic acid in 5 g of . Assuming 84%
o
dimerisation of acid. The boiling point and of . Are 46.2 and 2.3 k. kg. respectively.
18. (i) Describe how the molecular mass of a substance can be determined by a method based on
measurement of osmotic pressure. [E-MD]
(ii) A doctor advised a person suffering from high blood pressure to take less quantity of common
salt. Explain.
(iii)What mass of ethylene glycol (molar mass = 62 g/mol) must be added to 5.5 kg of water to lower
the freezing point of water from to ? ( for water = 1.86 k.kg )
19. (i) How will you determine the molecular mass from relative lowering of vapour pressure? [E-MD]
(ii) How much urea (mol. Mass = 60 g/mol) should be dissolved in 50 g of water so that its vapour
pressure at room temperature is reduced by 25%? Calculate molality of the solution obtained.