Determination of molar mass from osmotic pressure
According to van’t Hoff equation
c= n / V
Here, n= number of moles of solute dissolved in ‘V’ litre of the solution.
Therefore, π = n/V . RT or
If the solution is prepared by dissolving wB g of nonvolatile solute in wA g of solvent, then the number of moles ‘n’ is,
Since,MB = molar mass of the solute
Substituting the ‘n’ in 9.32, we get,
From the equation 9.33, molar mass of the solute can be calculated.