Question
The vapour pressure of pure benzene is 22 mm & that of pure toulene is 75 mm at 200 C . what is the composition of the solution of these two components that has a vapour pressure of 50 mm at this temperaure? what is the composition of vapour in equilibrium with this solution?
Joshi sir comment
x22+(1-x)75 = 50
so 22x+75-75x = 50
so 53x = 25 so x = 25/53
so ratio of there amounts (in mole) = 25/53 : 28//53 = 25:28
now ratio in vapour form can be obtained by this method
v. p. of pure benzene = 25/53 * 22 = 550/53
and v. p. of pure toluene = 28/53 * 75 = 2100/53
so ratio = (550/53)/(2100/53) = 550/2100 = 55/210 = 11/42