Depression in freezing point Formula
Freezing point:
The freezing point of substance may be defined as the temperature of which vapour pressure of liquid Is in Equilibrium with vapour pressure of solid.
Depression in freezing point
It is the difference between freezing point of pure solvent and freezing point of solution.
Formula:
∆Tf = Tf º – Tf
∆Tf = decrease freezing point
Tfº = freezing point of pure solvent
Tf = freezing point of solution
- The depression In freezing point Is directly proportional to the Molal concentration.
∆Tf α m
Where , m = molality
∆Tf = Kf × m……. (1)
Kf = Molal depression constant or cryoscopic constant
Cryoscopic constant is the depression in freezing point produced by dissolving one Mole of solute in 1 kg of solvent.
Unit of Kf = KKgmol-1