8 According to Raoult’s law,
when a non-volatile solid is added to the solvent
its vapour pressure decreases and now it would
become equal to that of solid solvent at lower
temperature Thus, the freezing point of the
solvent decreases Let 
0
fT  be the freezing point of pure solvent
and 
fT  be its freezing point when non-volatile
solute is dissolved in it