Freezing-point depression is the process in which adding a note volatile salute to a solvent decreases the freezing point of the solvent.
The freezing point of a solution is less than the freezing point of the pure solvent.
ΔTf = i Kf m
ΔTf – freezing point depression, i- Vont’ hoff factor, Kf – freezing point depression constant, m – molality (mole/kg)
75g of ethylene glycol (C2H6O2) is added to 675g of water. Calculate the freezing point depression. (Kf of H 2O = 1.86 degrees C/m and the molar mass of C2H6O2 = 62.07g/mol)
Apply the freezing point depression formula;
m = 75g/.675kg = 1.790mol/Kg
Freezing point depression, dT = 1* 1.86 degrees C/m x 1.790m = 3.329˚C