Answer the following. How molar mass of a solute is determined by osmotic pressure measurement? - Chemistry

Exercise | Q 3.6 | Page 46

Answer the following.

How molar mass of a solute is determined by osmotic pressure measurement?

Solution



1. For very dilute solutions, the osmotic pressure follows the equation,

π=n2RTV        ....(1)

2. If the mass of solute in V litres of a solution is W2 and its molar mass is

M2, then n2=W2M2

Substituting the value of n2 in equation (1), we get

π=W2RTM2V

∴ M2=W2RTπV

This formula can be used for the calculation of molar mass of a nonionic solute (i.e., nonelectrolyte), by osmotic pressure measurement.