An equimolar mix of benzene `&` toluene is prepared the total V.P. of this mix as a fraction of mole fraction of benzene is found to be `P_(T)=200+400X_(ben)`.
(a) Calculate composition of vapours of this mix. [Assume that the no. of moles going into vapour phase is negligible in comparsion to no. of moles present in liq. phase].
(b) If the vapour above liq in part `A` are collected `&` are condensed into a new liquid calculate composition of vapours of this new liq.

Explanation

(a) `P_("Benzene")^0=600" mm of Hg ,"`
`P_("Toloune")^0=200" mm of Hg"`
`P_T=1/2xx600+1/2xx200=400 "mm of Hg"`
`P_("benz")=x_(ben)'P_(ben)^0` `=y_(ben)P_T`
`y_("benzene")=(1//2xx600)/400=3/4=75%`
`y_("Tolouence")=1/4=25%`
(b)
`P_T=3/4xx600+1/4xx200=500rArry_(ben)=(3//4xx600)/500`
= 0.9 = 90%
`P_T=3/4xx600+1/4xx200=500rArry_(ben)=(3//4xx600)/500`