A liquid mixture containing $50$ mol$\%$ n$-$heptane $($A$)$ and $50$ mol$\%$ n$-$octane $($B$),$ at $303$ K$,$ is to be continuously flash$-$vaporized at a temperature of $350$ K to vaporize $30$ mol$\%$ of the feed. What will be the composition of the vapor and liq$-$ uid and the pressure in the separator if it behaves as an ideal stage?

keeping in mind that Answer: yD $=0\mathrm{.}654$