Benzene and toluene form an ideal solution. The vapour pressures of benzene and toluene are 75 mm an — Solutions and Colligative Properties Chemistry Question

💡 Solution & Explanation

$Y_B = P_B / P_T \implies 0.75 = (75 \cdot X_B) / P_{total}$. Also $Y_T = P_T / P_{total} \implies 0.25 = (25 \cdot X_T) / P_{total}$. Since $X_B + X_T = 1 \implies \frac{0.75 P_{total}}{75} + \frac{0.25 P_{total}}{25} = 1 \implies P_{total} (0.01 + 0.01) = 1 \implies P_{total} (0.02) = 1 \implies P_{total} = 50$ mm. Therefore, correct answer is B.