Question
Which of the following statements about the composition of the vapour over an ideal 1 : 1 $$molar$$ mixture of benzene and toluene is correct? Assume that the temperature is constant at $${25^ \circ }C.$$
( Given, vapour pressure data at $${25^ \circ }C,$$ benzene $$ = 12.8\,kPa,$$ toluene $$ = 3.85\,kPa$$ )
A.
The vapour will contain a higher percentage of toluene
B.
The vapour will contain equal amounts of benzene and toluene
C.
Not enough information is given to make a prediction
D.
The vapour will contain a higher percentage of benzene
Answer :
The vapour will contain a higher percentage of benzene
Solution :
Since, component having higher vapour pressure will have higher percentage in vapour phase. Benzene has vapour pressure $$12.8$$ $$kPa$$ which is greater than toluene $$3.85$$ $$kPa.$$
Therefore, the vapour will contain a higher percentage of benzene.