Question

What are the units of molal depression constant or cryoscopic constant?

Answer 1

The freezing point depression,

 ΔT_f is given by, 

ΔT_f = K_f × m where m is molality in mol kg^-1 and K_f is molal depression constant or cryoscopic constant.

∴ K_f has unit K kg mol^-1(or °C kg mol^-1) 

Therefore,

cryoscopic constant is the depression in freezing point produced by 1 molal solution of a nonvolatile solute.