Question

Molal depression constant depends upon
A. Nature of solute
B. Nature of solvent
C. Heat of solutions of the solute in the solvent
D. Vapour pressure of the solution

Answer 1

The freezing point depression of solutions of nonelectrolytes has been determined to be equal to the molality $\left( M \right)$ of the solute times a proportionality constant called the molal freezing point depression constant.

Complete step-by-step answer: Whenever a solute is dissolved in solvent there is always a depression in freezing point means after the solute dissolves in solvent the freezing point of solvent decreases.
Depression in freezing point is denoted by $\Delta T$ and depression in freezing point is directly proportional to the molality of solvent.
$\Delta T \propto M$
Here M is molarity of solvent
For removing proportional signs we need a constant and this constant is a molal depression constant.
$\Delta T = {K_f}.M$
And this molal depression constant is represented by ${K_f}$.
As molal depression constant depends upon quality of solvent and molality is the nature of solvent

Therefore the correct answer will be option number B, that is molal depression constant depends upon nature of the solvent.

Note: Freezing point depression is a colligative property observed in solutions that results from the introduction of solute molecules to a solvent. The freezing points of solutions are all lower than that of the pure solvent and are directly proportional to the molality of the solute.