Question

A 0.1 molal aqueous solution of a weak acid is 30% ionized. If K_f for water is 1 .86°C/m, the freezing point of the solution will be

(a) - 0.18°C

(b) - 0.54°C

(c) - 0.36°C

(d) - 0.24°C

Answer 1

Correct option (d) - 0.24°C

Explanation :

We know that

Here i is van't Hoff's factor.

i for weak acid is 1 + α.

Here α is degree of dissociation i.e., 30/100 = 0.3