Water and chlorobenzene are immiscible liquids. Their mixture boils at `89^(@)C` under a redued pressure of `7.7 xx10^(4)Pa`. The vapour pressure of pure water at `89^(@)C` is `7xx10^(4)Pa`. Weight per ccent of chlorobenzene in the distillate is `:`

Options

A. 50
B. 60
C. 70
D. 80

Answer

C

Explanation

`PV=nRT`
`P_("mix")=7.82xx10^(4)Pa`
P_(2)+P_(1)=7.82xx10^(4)Pa`
`P_(1)=7.03xx10^(4)Pa`
`therefore P_(2)=0.79xx10^(4)Pa`
`Ppropn`
`therefore (w_(2)m_(1))/(w_(1)m_(2))=(P_(2))/(P_(1))`
`w_(2)=(P_(2)m_(2))/(p_(1)m_(1))=(0.79xx10^(4)xx112.5)/(70.3xx10^(4)xx18)=0.70`