For an ideal solution of A and B, is the mole fraction of A in the vapour phase at equilibrium. Whic — Solutions and Colligative Properties Chemistry Question

💡 Solution & Explanation

Using Dalton's and Raoult's laws, $Y_A = P_A^\circ X_A / P_{\text{total}}$. From this, the relationship can be derived as: $\frac{1}{P_{\text{total}}} = \frac{Y_A}{P_A^\circ} + \frac{Y_B}{P_B^\circ} = \frac{Y_A}{P_A^\circ} + \frac{1 - Y_A}{P_B^\circ} = \frac{1}{P_B^\circ} + \left(\frac{1}{P_A^\circ} - \frac{1}{P_B^\circ}\right)Y_A$. This equation is linear ($y = mx + c$), meaning the plot of $1/P_{\text{total}}$ vs $Y_A$ is a straight line. Therefore, correct answer is C.