Question $6$

A liquid containing $50$mol$\%n-$Hexane and $50$mol$\%n-$Octane is required to be separated

under flash distillation until $65\%$ of the liquid is distilled. The vapor pressure$-$equilibrium data

for the system n$-$hexane and n$-$octane at $101\mathrm{.}32$kPa is given below:

Vapor$-$liquid equilibrium data for $n-$Hexane $-n-$Octane mixture

a$)$ By applying the Raoult's Law and Dalton Law, determine the mol fraction of hexane

in liquid and vapor phase at temperature $79\mathrm{.}4$ to $93\mathrm{.}3C$

Determine the composition of vapor $(y_A)$ and liquid $(x_A)$ at an equilibrium stage.

c$)$ Further the vapor stream from the flash distillation is subjected to a condenser before

it fed to a second flash distillation. Again $65$mol$\%$ of the liquid is distillated.

Determine the composition of the second overhead product $(y_A).$