A total of $100mo\frac{l}{s}$ of a saturated $($dew point$)$ vapor consisting of $60$mol$\%$ benzene and $40$

mol$\%$ toluene is fed to a distillation column containing equilibrium trays, a TC$,$ and a PR$.$ A

reflux ratio of $2\mathrm{.}0$ produces a $65mo\frac{l}{s}$ of a distillate with $0\mathrm{.}89$mol$\frac{B}{m}ol.$ How many trays

are required and which one will be the optimum feed tray?

a$.$ Draw a process flow diagram

b$.$ Draw the TOL, q$-$line, and BOL on the xy graph $.$

c$.$ Using the "Step off the Stages" method to determine how many trays are required

and which one will be the optimum feed tray $.$