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Q 21 :

Match List I and List II. [2023]

List I

List II

A. Osmosis

I. Solvent molecules pass through semipermeable membrane towards solvent side.

B. Reverse osmosis

II. Movement of charged colloidal particles under the influence of applied electric potential towards oppositely charged electrodes.

C. Electro-osmosis

III. Solvent molecules pass through semipermeable membrane towards solution side.

D. Electrophoresis

IV. Dispersion medium moves in an electric field.

Choose the correct answer from the options given below:

A-I, B-III, C-II, D-IV
A-III, B-I, C-IV, D-II
A-I, B-III, C-IV, D-II
A-III, B-I, C-II, D-IV

1

2

3

4

(2)

(i) Electroosmosis: When movement of colloidal particles is prevented by some suitable means (porous diaphragm or semipermeable membranes), it is observed that the D.M. begins to move in an electric field. This phenomenon is termed electroosmosis.

(ii) Solvent molecules pass through semi-permeable membrane towards solvent side is termed as reverse osmosis.

(iii) When an electric potential is applied across two platinum electrodes dipping in a colloidal solution, the colloidal particles move towards one or the other electrode. The movement of colloidal particles under an applied electric potential is called electrophoresis.

(iv) Solvent molecules pass through semipermeable membrane towards the solution side is termed as osmosis.

Q 22 :

Match List I with List II.   [2023]

List I

List II

A. van’t Hoff factor, $i$

I. Cryoscopic constant

B.   $k_{f}$

II.  Isotonic solutions

C. Solutions with same osmotic pressure

III. $\frac{Normal molar mass}{Abnormal molar mass}$

D. Azeotropes

IV. Solutions with same composition of vapour above it

Choose the correct answer from the options given below:

A–III, B–I, C–IV, D–II
A–I, B–III, C–II, D–IV
A–III, B–II, C–I, D–IV
A–III, B–I, C–II, D–IV

1

2

3

4

(4)

(A) Van't Hoff factor $= {\frac{Normal molar mass}{Abnormal molar mass}}$

(B) $K_{f} \Rightarrow$ Cryoscopic constant.

(C) Solutions with same osmotic pressure $\Rightarrow$ Isotonic solution.

(D) Azeotropes $\Rightarrow$ Solutions with same composition of vapour above it.

Q 23 :

Evaluate the following statements for their correctness.

(A) The elevation in boiling point temperature of water will be same for 0.1 M NaCl and 0.1 M urea.

(B) Azeotropic mixtures boil without change in their composition.

(C) Osmosis always takes place from hypertonic to hypotonic solution.

(D) The density of 32% $H_{2} {SO}_{4}$ solution having molarity 4.09 M is approximately 1.26 g ${mL}^{- 1}$ .

(E) A negatively charged sol is obtained when $KI$ solution is added to silver nitrate solution.

Choose the correct answer from the options given below: [2023]

B and D only
B, D and E only
A and C only
A, B and D only

1

2

3

4

(1)

(A) $Δ T_{b}$ is not same, as $' i'$ value is different for two solutions.

(B) Azeotropic mixture: Liquid mixtures which distill over without changes in composition are called constant boiling mixtures or azeotropes or azeotropic mixtures.

(C) Osmosis takes place from hypotonic to hypertonic.

(D) $M = \frac{32 \times 10 \times 1.26}{98} \approx 4.09 M$

(E) When $KI$ is added to ${AgNO}_{3}$ solution then positively charged sol is formed.

Q 24 :

The osmotic pressure of solution of PVC in cyclohexanone at 300 K are plotted on the graph. The molar mass of PVC is ______ g ${mol}^{- 1}$ (Nearest integer).

[IMAGE 139]

(Given: R = 0.083 L atm $K^{- 1}$ ${mol}^{- 1}$ ) [2023]

0%

(41500)

Assuming $π$ vs C graph, then slope = $\frac{R T}{M}$

$= \frac{0.083 \times 300}{M} = 6 \times 10^{- 4}$ or $M = 41500 g/mol$

Q 25 :

The number of pairs of the solutions having the same value of the osmotic pressure from the following is _____. (Assume 100% ionization) [2023]

A.   $0.500 M C_{2} H_{5} OH (aq) and 0.25 M KBr(aq)$

B.   $0.100 M K_{4} [Fe {(CN)}_{6}] (aq)$ $and$ $0.100 M {FeSO}_{4} {({NH}_{4})}_{2} {SO}_{4} (aq)$

C.   $0.05 M K_{4} [Fe {(CN)}_{6}] (aq)$ $and$ $0.25 M NaCl (aq)$

D.   $0.15 M NaCl (aq)$ $and$ $0.1 M {BaCl}_{2} (aq)$

E.   $0.02 M KCl . {MgCl}_{2} . 6 H_{2} O (aq)$ $and$ $0.05 M KCl (aq)$

0%

(4)

$π \propto i C$

A, B, D and E

Q 26 :

A solution containing 2 g of a non-volatile solute in 20 g of water boils at 373.52 K. The molecular mass of the solute is ______ g ${mol}^{- 1}$ . (Nearest Integer)

Given, water boils at 373 K, $K_{b}$ for water = 0.52 K kg ${mol}^{- 1}$ . [2023]

0%

(100)

$Δ T_{b} = k_{b} m$

$(373.52 - 373) = 0.52 \times (\frac{2 \times 1000}{M \times 20})$

$M = \frac{2 \times 1000}{20} = 100 g/mol$

$Molecular mass of solute = 100 g/mol .$

Q 27 :

At 27°C, a solution containing 2.5 g of solute in 250.0 mL of solution exerts an osmotic pressure of 400 Pa. The molar mass of the solute is ______ g ${mol}^{- 1}$ .

(Given: R = 0.083 L bar $K^{- 1}$ ${mol}^{- 1}$ ) [2023]

0%

(62250)

$π = C R T$

$\frac{400 \times 10^{- 5}}{(1.01325)} = [\frac{2.5 \times 1000}{M_{solute} \times 250}] (0.083 \times 300)$

$400 \times 10^{- 5} = \frac{10}{M_{solute}} \times 0.083 \times 300$

$M_{solute} = \frac{10 \times 0.083 \times 300}{400} \times 10^{5}$

$= [\frac{10 \times 0.083 \times 3}{4}] \times 10^{5} = 62250 gram/mole$

Q 28 :

25 mL of an aqueous solution of KCl was found to required 20 mL of 1 M ${AgNO}_{3}$ solution when titrated using $K_{2} {CrO}_{4}$ as an indicator. What is the depression in freezing point of KCl solution of the given concentration? (Nearest integer). (Given: $K_{f}$ = 2.0 K kg ${mol}^{- 1}$ )

Assume

(1) 100% ionization and

(2) density of the aqueous solution as 1 g ${mL}^{- 1}$ [2023]

0%

(3)

${25 mL KCl v/s 20 mL of 1M AgNO}_{3}$

$Molarity of KCl = \frac{20 \times 1}{25} = \frac{4}{5} M = \frac{0.8 mol}{L}$

$1 L solution has 0.8 mol KCl$

$Δ T_{f} = i k_{f} m$

$= 2 \times 2 \times 0.8 = 3.2 \approx 3$

Q 29 :

20% of acetic acid is dissociated when its 5 g is added to 500 mL of water. The depression in freezing point of such water is ______ $\times 10^{- 3}$ °C. Atomic mass of C, H and O are 12, 1 and 16 a.m.u. respectively. (Given: Molal depression constant and density of water are 1.86 K kg ${mol}^{- 1}$ and 1 g ${cm}^{- 3}$ respectively) [2023]

0%

(372)

$α = 0.2$

$i = 1 + (n - 1) α = 1.2$

$Δ T_{f} = i k_{f} m = 1.2 \times 1.86 \times \frac{5 \times 1000}{60 \times 500}$

$= 0.372 = 372 \times 10^{- 3} ° C$

Q 30 :

Consider the following pairs of solution which will be isotonic at the same temperature. The number of pairs of solutions is/are __________. [2023]

A. 1 M aq. NaCl and 2 M aq. urea

B. 1 M aq. ${CaCl}_{2}$ and 1.5 M aq. KCl

C. 1.5 M aq. ${AlCl}_{3}$ and 2 M aq. ${Na}_{2} {SO}_{4}$

D. 2.5 M aq. KCl and 1 M aq. ${Al}_{2} {({SO}_{4})}_{3}$

0%

(4)

For isotonic solution $i_{1} c_{1} = i_{2} c_{2}$

Solution	$i_{1} c_{1}$	$i_{2} c_{2}$
A	2	2
B	3	3
C	6	6
D	5	5

List I	List II
A. Osmosis	I. Solvent molecules pass through semipermeable membrane towards solvent side.
B. Reverse osmosis	II. Movement of charged colloidal particles under the influence of applied electric potential towards oppositely charged electrodes.
C. Electro-osmosis	III. Solvent molecules pass through semipermeable membrane towards solution side.
D. Electrophoresis	IV. Dispersion medium moves in an electric field.

Topic Question Set

Q 24 :

The osmotic pressure of solution of PVC in cyclohexanone at 300 K are plotted on the graph. The molar mass of PVC is ______ g ${mol}^{- 1}$ (Nearest integer).

[IMAGE 139]

(Given: R = 0.083 L atm $K^{- 1}$ ${mol}^{- 1}$ ) [2023]

0%

0%

Q 26 :

A solution containing 2 g of a non-volatile solute in 20 g of water boils at 373.52 K. The molecular mass of the solute is ______ g ${mol}^{- 1}$ . (Nearest Integer)

Given, water boils at 373 K, $K_{b}$ for water = 0.52 K kg ${mol}^{- 1}$ . [2023]

0%

Q 27 :

At 27°C, a solution containing 2.5 g of solute in 250.0 mL of solution exerts an osmotic pressure of 400 Pa. The molar mass of the solute is ______ g ${mol}^{- 1}$ .

(Given: R = 0.083 L bar $K^{- 1}$ ${mol}^{- 1}$ ) [2023]

0%

0%

0%

0%

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List I	List II
A. van’t Hoff factor, $i$	I. Cryoscopic constant
B. $k_{f}$	II. Isotonic solutions
C. Solutions with same osmotic pressure	III. $\frac{Normal molar mass}{Abnormal molar mass}$
D. Azeotropes	IV. Solutions with same composition of vapour above it