A
pure solvent freezes at 12.0 c. a solution of 0.980 g of the solute
and 13.870 g of solvent froze at 5.1 c. the molar mass of the
solute is 178.2 g/mol. calculate the freezing point depression
constant, kf for the solvent.

for solvent is

Explanation:

, where is depression in freezing point and m is molality of solution

Molality of solution (m) = (moles of solute/mass of solvent in kg)

                                      =

                                      = 0.396 mol/kg

So,