Question

Liquid $'M'$ and liquid $'N'$ form an ideal solution. The vapour pressures of pure liquids $'M'$ and $'N'$ are $450$ and $700\, mmHg$, respectively, at the same temperature. Then correct statement is: ($x_M$ = Mole fraction of $'M'$ in solution ; $x_N$ = Mole fraction of $'N'$ in solution ; $y_M$ = Mole fraction of $'M'$ in vapour phase ; $y_N$ = Mole fraction of $'N'$ in vapour phase)

• A. $(x_M - y_M) < (x_N - y_N)$
• B. $\frac{x_M}{x_N} < \frac{y_M}{y_N}$
• C. $\frac{x_M}{x_N} > \frac{y_M}{y_N}$
• D. $\frac{x_M}{x_N} = \frac{y_M}{y_N}$

Answer 1

Answer: (C)

$\because \, \, P^{\circ}_{N} > P^{\circ}_{M}$
$\therefore \, \, \, €y_N > x_N$
& $X_M > y_M$
Multiply we get
$y_N X_M > X_N y_M$