Question

Vapour pressure of a pure liquid solvent A is $0.80\,\mathrm{atm}$. When a non-volatile solute B is added to the solvent, its vapour pressure drops to $0.60\,\mathrm{atm}$. The mole fraction of components A and B in the solution are respectively:}

• A. 0.75, 0.25
• B. 0.25, 0.75
• C. 0.60, 0.40
• D. 0.40, 0.60

Hint:

For a non-volatile solute: \[ X_{\text{solvent}} = \frac{P_{\text{solution}}}{P^\circ_{\text{solvent}}} \] Then use \[ X_{\text{solute}}=1-X_{\text{solvent}}. \]

Answer 1

The Correct Option is A