Question

During depression of freezing point in a solution the following are in equilibrium:
A) liquid solvent, solid solvent
B) liquid solvent, solid solute
C) liquid solute, solid solute
D) liquid solute, solid solvent

Answer 1

In the given question freezing point of a solution at equilibrium condition has been understood, at the depression of freezing point what will be the state of the solvent will occur. As the freezing points of several solutions are all lower than as compared to the pure solvent.

Complete answer:
According to the question at the time of depression of freezing point within a solution, the liquid solvent and solid solvent are in equilibrium condition. So, throughout the freezing of a solution, only the solvent gets frozen and the equilibrium condition exists within the solid and liquid forms of the solvent.
We know that the Vapor pressure of a solid and liquid forms must be the same at their freezing point, it is because, the system would not be at equilibrium, and the lowering of the vapor pressure will leads to the lowering of temperature at though the vapor pressures of the liquid and frozen forms of the solution will be remain equal.

Hence, the correct answer is option ‘A’.

Note: As the freezing point depression is a colligative property observed in solutions that results from the introduction of solute molecules to a solvent. Therefore, the Freezing-point depression is the decreasing of the freezing point of a solvent when the addition of a non-volatile solute is done.