According to Raoult's law mole fraction of solute in solution is given by formula
According to Raoult's law mole fraction of solute in solution is given by formula
$\frac{\Delta \mathrm{P}}{\mathrm{P}_1^0}$
$\frac{\mathrm{P}_1^0}{\mathrm{P}_1}$
$\frac{\mathrm{P}_1^0}{\Delta \mathrm{P}}$
$\frac{\mathrm{P}_1}{\mathrm{P}_1^0}$
Solution
$P_1=$ Vapour pressure of solution
$\mathrm{P}_1^0=$ Vapour pressure of pure solvent
Mole fraction of solute $=\frac{\mathrm{P}_1^0-\mathrm{P}_1}{\mathrm{P}_1^0}=\frac{\Delta \mathrm{P}}{\mathrm{P}_1^0}$