Depression in Freezing Point

Recall that the freezing point of a liquid is the temperature at which liquid and solid are in equilibrium and the two phases have the same vapour pressure.

The general experimental observation is that the freezing point of a solvent is lowered by dissolving a nonvolatile solute into it. Thus, the freezing point of a solution containing a nonvolatile solute is lower than that of the pure solvent. …