**According to van’t Hoff equation **

π = CRT

C = n / V

Here n = number of moles of solute dissolved in ‘V’ litre of the solution.

π = \(\frac{n}{V}\).RT = πV = nRT

If the solution is prepared by dissolving W_{B} of the non-volatile solute in W_{A} g of solvent, then the number of moles of ‘n’ is

\(n=\frac{W_B}{M_B}\)

where

M_{B} = molar mass of the solute

Substituting n value, we get

From the above equation, we can calculate the molar mass of the solute.