36)
Thus for determining the molar mass of the solute we should know
the quantities w1, w2, DTf, along with the molal freezing point depression
constant The values of Kf and Kb, which depend upon the nature of the
solvent, can be ascertained from the following relations Kf
=
2
1
f
fus
 × 
 × 
1000 × 
R
M
T
H
(1 37)
Kb
=
2
1
b
vap
 × 
1000 ×  × 
R
M
T
H
(1