Question

What is the composition of the vapour which is in equilibrium at ${30}^{\circ }C$ with a benzene-toluene solution with a mole fraction of benzene of $0.40?$ and with a mole fraction of benzene of $0.60?$

[$P_b^{{}^{\circ }}=119$ torr and $P_t^{{}^{\circ }}=37$ torr]

Answer 1

We know $Y_B=\frac{X_B{P}_B}{X_t{P}_t+X_B{P}_B}$

$a)Y_B=\frac{0.40\times 119}{0.40\times 119+0.60\times 37}$

$=0.682$

Now, $Y_t=\frac{X_t{P}_t}{X_t{P}_t+X_B{P}_B}$

$Y_t=\frac{0.60\times 37}{0.40\times 119+0.60\times 37}$

$Y_t=0.318$

$b)X_B=0.6;$

$Y_B=\frac{0.6\times 119}{0.6\times 119+0.60\times 37}=0.829;Y_t=1.000-0.829$

$=0.171$