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_("Beazene")^(0)=600 mm of Hg`
`P_("Totoune")^(0)=200 mm of Hg`
`P_(T)=(1)/(2)xx600+(1)/(2)xx200=400 mm of Hg`
`P_("benz")=x_("ben") 'P_("ben")^(0)=y_("ben")P_(T)`.
`y_("benzene")=(1//2xx600)/(400)=(3)/(4)=75% , , y_("Toloune")=(1)/(4)=25%`
(b)
`P_(T)=(3)/(4)xx600+(1)/(4)xx200=500 rArr y_("ben")=(3//4xx600)/(500)=0.9=90%`
`y_("Toluene")=0.1=10%`