The vapour pressure of pure liquid ‘B’ at 27°C is — Solutions and Colligative Properties Chemistry Question

💡 Solution & Explanation

Molar volume of liquid B ($V_{l,B}$) = $50 / 1.0 = 50 \text{ ml/mol} = 0.05 \text{ L/mol}$. Molar volume of vapour B ($V_{v,B}$) = $7600 \times 0.05 = 380 \text{ L/mol}$. $P_B^\circ \cdot V_{v,B} = RT \implies P_B^\circ = (0.08 \times 300) / 380 = 24 / 380 \text{ atm} = (24 \times 760) / 380 \text{ torr} = 48 \text{ torr}$. Therefore, correct answer is B.