Freezing Point Depression is based on 3 things:
The identity of the solvent (which controls the Kf)
The concentration (measured in molal)
The VANT HOFF factor (which is based on the identity of the solute).

The more particles a solute breaks up into when it dissolves, the higher the Van't Hoff factor, the GREATER the freezing point depression and the LOWER the freezing point.

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