Assignment-3 (chemistry)---SOLUTIONS

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1. The elevation in boiling is given by

a. ∆Tb = Kb.m

b. ∆Tb = 1000 Kb * M

c. ∆ Tb = Kb nb/ Wa

d. ∆Tb =KbWa / nb

2. Osmotic pressure observed when benzoic acid is dissolve in benzene is less

than that expected from theoretical considerations. This is because

a. benzene acid is an organic solute

b. benzoic acid gets associated in Benzene

c. benzoic acid has higher molar than benzene

d. benzoic acid gets dissociated in Benzene

3. The number of oxalic acid molecules in 100 mL of 0.22 N oxalic acid

solution is

a. 6.022 × 10²³

b. 10^-3

c. 6.022 × 10²⁰

d. None

4. The volume of water to be added N/2 HCL to prepare 500 cm³ of N/10

solution is

a. 45 cm³

b. 400 cm³

c. 450 cm³

d. 100 cm

5. The freezing point of 0.05 molal solution of non-eletrolyte in water is

a. - 1.86⁰C

b. - 0.93⁰C

c. - 0.093⁰C

d. 0.03⁰C

6. The average osmotic pressure of benzoic acid is 7.8 bar at 37⁰C. What is the

concentration of aqueous KCl solution that could be used in blood stream?

a. 0.16 mol L^-1

b. 0.60 mol L^-1

c. 0.32 mol L^-1

d. 0.45 mol L^-1

7. The mol. wt of urea is 60 & of glucose is 180. The osmotic pressure of

0.001 M solution of glucose & urea will be in the ratio of

a. 1 : 3

b. 3 : 1

c. 1 : 1

d. 1 : √3

8. The osmotic pressure of 0.1 M solution of KNO₃ & CH₃COOH are P1 & P2

respectively. Thus,

a. P1 > P2

b. P1 < style="">

c. P1 = P2

d. P2/(P1+P2) = P1/(P1+P2)

9. The vapour pressure of a solution of 5 g of non electrolyte in 100 g of water

at a particular temperature is 2985 Nm^-2. The vapour pressure of pure

water at that temperature is 3000 Nm^-2. The molecular weight of the solute

is

a. 180

b. 90

c. 270

d. 200

10. The mol fraction of solute in 2.5 m aqueous solution is

a. 0.043

b. 0.43

c. 4.3

d. 43

11. 1.00 g of a non-electrolyte solute (molar mass 250 g mol^-1) was dissolved in

51.2g of benzene. If the freezing point depression constant. K_f of benzene is 5.12 K

kg mol^-1 the freezing point benzene will be lowered by

a. 0.5 K

b. 0.2 K

c. 0.4 K

d. 0.3 K

12. KBr is 80% dissociated in aqueous solution of 0.5 M concentration (Given

K_f for water = 1.86 K kg mol^-1) The solution freezes at

a. 271.326 K

b. 272 k

c. 270.5 K

d. 268.5 K

e. 269 K

13. What will be the weight of nitric acid dissolved per liter of the solution if

25 mL of this solution neutralizes 20 mL of 0.15 N NaOH

a. 63 g

b. 0.12 g

c. 7.56 g

d. 15.012 g

14. The depression in f.p. of 0.01 m aqueous solution of urea, sodium chloride

& Sodium sulphate is in the ratio

a. 1 : 1 : 1

b. 1 : 2 : 3

c. 1 : 2 : 4

d. 2 : 2 : 3

15. The osmotic pressure of a solution containing 4.0 g of solute (molar mass

246)per liter at 27⁰C is (R = 0.082 L atm K^-1 mol^-1);

a. 0.1 atm

b. 0.2 atm

c. 0.4 atm

d. 0.8

16. 50 cm³ of ethanol glycol is dissolved in 50 g of water a solution having

freezing point -34⁰C. Assuming ideal behaviour, density of ethylene glycol

in (g/cm³)is

a. 1.133

b. 2.266

c. 0.566

d. none of these

17. The normality of orthophosphoric acid (H₃PO₄) having purity of 70%

(w/w) will be (d=1.54 g/cc)

a. 66

b. 33

c. 99

d. 132

18. 25 ml sol of brimium hydroxide on titration with a 0.1 molar sol of HCl

gave a titre value of 35 mL. The molarity of Brimium hydroxide sol was

a. 0.28

b. 0.35

c. 0.07

d. 0.14 M

19. 75.2 g of C₆H₅OH (phenol) is dissolved in a solvent of K_f= 14. If the

depression in freezing point is 7K then the % of phenol the Dimerisis is

a. 65%

b. 75%

c. 80%

d. 85%

20. What is the molarity of 0.2 N Na₂CO₃ sol?

a. 0.05 M

b. 0.04M

c. 0.01M

d. 0.02 M