Determine the freezing point of a 0.51 molal
solution of benzoic acid in chloroform. chloroform
has a freezing point of -63.5°c and a freezing
point depression constant of 4.70°c. kg/mol.
what is the freezing point of this solution?
°c

-65.897°C.

Explanation:

where, ΔTf is the depression in freezing point of chloroform solution.

Kf is the molal depression constant of chloroform (Kf = 4.70°C.kg/mol).

m is the molality of the solution (m = 0.51 m).

∴ ΔTf = Kf.m = (4.70°C.kg/mol)(0.51 m) = 2.397°C.

∴ The freezing point of the solution = (freezing point of chloroform) - ΔTf = (-63.5°C) - (2.397°C) = -65.897°C.