Why does a solute depress the freezing point?

a. the solute is colder than the solvent.
b. the solute disrupts crystal formation by the solvent.
c. the solute tends to sink to the bottom of the solution.
d. the solute has bigger molecules than the solvent.

Option (C) is the correct answer.

Explanation:

Freezing point depression is defined as the decrease in temperature of freezing of a solvent when a non-volatile solute is added into it.

This decrease in temperature arises because addition of solute particles into the solvent tend to disrupt the crystal formation of the solvents.

As a result, particles does not come closer to each other. Hence, we need to provide more lower temperature due to which there will be formation of crystal lattice in order to form the solid.

Thus, we can conclude that a solute depress the freezing point because the solute disrupts crystal formation by the solvent.