Van't Hoff factor (i) is given by the expression:

a. $i=\frac{\text{ Normal molar mass }}{\text{abnormal molar mass.}}$

b. $i=\frac{\text{ Abnormal molar mass }}{\text{normal molar mass. }}$

c. $i=\frac{\text{ Observed colligative property }}{\text{calculated colligative property. }}$

d. $i=\frac{\text{ Calculated colligative property }}{\text{observed colligative property.}}$

The correct choice among the given options are:

1. (a, b)

2. (b, c)

3. (c, d)

4. (a, c)

2 g of benzoic acid (C₆H₅COOH) dissolved in 25 g of benzene shows a depression in freezing point equal to 1.62 K. Molal depression constant for benzene is 4.9 K kg mol^–1. The percentage association of acid if it forms dimer in solution is:

1. 98.5%
2. 99.2 %
3. 97.5 %
4. 95.2 %

The values of van’t Hoff factors for KCl, NaCl and K₂SO₄ respectively are:

Three aqueous solutions of NaCl are labelled as ‘A', ‘B’ and ‘C with concentrations 0.1 M, 0.01 M and 0.001 M, respectively. The value of van’t Hoff factor for these solutions will be in the order of :

1. i_A < i_B < i_C

2. i_A > i_B > i_C

3. i_A = i_B = i_C

4. i_A < i_B > i_C

0.6 mL of acetic acid (CH₃COOH), having density 1.06 g mL^–1, is dissolved in 1 litre of water. The depression in freezing point observed for this strength of acid was 0.0205°C. The value of van’t Hoff factor and the dissociation constant of acid are respectively:

1. 1.041; 1.86 × 10^–5
2. 2.073; 1.86 × 10^–5
3. 0.091; 1.76 × 10^–5
4. 1.041; 1.76 × 10^–5

19.5 g of CH₂FCOOH is dissolved in 500 g of water. The van’t Hoff factor and dissociation constant of fluoroacetic acid will be respectively: ($∆{\mathrm{T}}_{\mathrm{f}}$ = 1.00 K )