Question

The vapour pressure of an ideal solution having 0.2 mole non-volatile solute and 0.8 mole solvent is 60 mm. The vapour pressure of pure solvent at this temperature will be:

• A. 120 mm
• B. 150 mm
• C. 60 mm
• D. 75 mm

Answer 1

The correct option is D 75 mm

we have,

$P_A=P_A^0{x}_A$

$60mm=P_A^0\times \frac{0.8}{0.2+0.8}$

$\frac{60}{0.8}=P_A^0$

$P_A^0=75mm$