explain why measurement of osmotic pressure is more widely used for determining the molar mass of macromolecules than the rise in boiling point or fall in freezing point temperature of their solution?

Osmotic pressure has advantages for finding out the molar mass over other collegative properties as pressure measurement is around room temperature and molarity is used instead of molality.

 As compared to the other collegative properties  its magnitude is large enough even for the dilute solution