When analyzing the vapour pressure phase diagrams for two-component ideal solutions plotted at a con — Solutions and Colligative Properties Chemistry Question

💡 Solution & Explanation

A is mathematically correct because $P = P_A^0 X_A + P_B^0 X_B$ forms a linear relationship. B is correct because the dew point boundary plotted against Y ($1/P = Y_A/P_A^0 + Y_B/P_B^0$) forms a curve. C is correct because $P_A = P_A^0 X_A$, so when $X_A=0$, $P_A=0$ (origin). D is incorrect; in a P vs X diagram, increasing the pressure condenses vapour into liquid, so the region above the highest curve represents the stable liquid phase.