100 kmol h-1 of a saturated liquid of mole fraction 0.545 benzene and 0.455 chlorobenzene is fed to a distillation column containing two equilibrium plates, a total condenser and a partial reboiler. The feed is introduced at the bottom plate. If the boil up ratio is 0.855 and the liquid to vapour ratio is 0.500 determine the composition of the bottoms product assuming constant molar overflow and a distillate mole fraction of 0.900 benzene.