Solutions Part 1

Given, Vapour pressure of benzene =75‌torr
Vapour pressure of toluene =22‌torr
mass of benzene in =78g
hence moles of benzene =‌

78

78

=1 mole
(mol. wt of benzene =78)
mass of toluene in solution =46g
hence moles of toluene =‌

46

92

=0.5 mole
Total moles of benzene and toluene =1.5‌mol
now partial pressure of benzene
=Pb∘×Xb=75×‌

1

1+0.5

=75×‌

1

1.5

=75×‌

2

3

=50 torr