The molecular weight of non-volatile solute can be determined experimentally by osmotic pressure method or by cryoscopy or by ebullisocopy Berkeley-Hartley method for isotomic presure is commonly used for aqueous solutions. Elevation in `b.pt.` or depression in `f.pt.` on addition of non-valatile solute in a solvent is read by Beckmann's thermometer.
Select the correct statement :

Options

A. Semi-permeable membrane of `Cu_(2)Fe(CN)_(6)` is soluble in water but insoluble in non-aqueous solvents.
B. Cryoscopy gives better results of mol.wt. of polymers of high mol.wt.
C. During freezing a solution, whole of the solution freezes.
D. Only solvent freezes at its `f.pt.` if solution is cooled.

Answer

D

Explanation

On cooling a solution a below its freezing point only solvent freezes out.