45 g of ethylene glycol (C₂H₆O₂) is mixed with 600 g of water. The freezing point of the solution is:

1. 268.15 K
2. 270.95 K
3. 272.75 K
4. 267.15 K

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