Question

For an ideal binary liquid solution with $P_A^{\circ }>P_B^{\circ }$ in which relation between $X_A$ (mole fraction of $A$ in liquid phase) and $Y_A$ (mole fraction of $A$ in vapour phase) is correct, $X_B$ and $Y_B$ are mole fraction of $B$ in liquid and vapour phase respectively

• A. $X_A=Y_A$
• B. $X_A>Y_A$
• C. $\frac{X_A}{X_B}<\frac{Y_A}{Y_B}$
• D. $X_A,Y_A,X_B$ and $Y_B$ cannot be correlated

Answer 1

Answer: (C)

$P_A^{\prime }=P_A^{\circ }\cdot X_A=P_T\cdot Y_A$

$P_B^{\prime }=P_B^{\circ }\cdot X_B=P_T\cdot Y_B$

$\therefore \frac{P_A^{\circ }}{P_B^{\circ }}\cdot \frac{X_A}{X_B}=\frac{Y_A}{Y_B}$

$\because \frac{P_A^{\circ }}{P_B^{\circ }}>1$

$\therefore \frac{X_A}{X_B}<\frac{Y_A}{Y_B}$