Dibromoethene $($DE$,$ p$*$DE$=22\mathrm{.}9$ kPa at $358$ K$)$ and dibromopropene$($DP$,$ p$*$DP $=17\mathrm{.}1$ kPa at $358$ K$)$ form a nearly ideal solution. If zDE $=0\mathrm{.}60,$ what is $($a$)$ P totalwhen the system isall liquid, $($b$)$ the composition of the vapor when the system isstill almost all liquid? $($ How could we decide to use z as liquid or vapour composition?$)$