Question

At 90°C the vapour pressure of l,2·dimethylbenzene is 20kPa and that of 1,3-dimethylbenzene is 18 kPa.w'hat is the composition of the vapour of an equimolar mixture of the two components?

Answer 1

Answer:

19kPa

Explanation:

the total pressure is given by $p_A+p_B$

The pressure $p_A=X_A\times P^0_A$

similarly $p_B=X_B\times P^0_B$

for equilibrium process let us consider both have one mole

so $x_A=\frac{1}{1+1}=0.5$

similarly $x_B=\frac{1}{1+1}=0.5$

so $P_A=0.5\times 20=10kPa$

$P_B=0.5\times 18=9kPa$

so total pressure=10+9=19 kPa