The top tray of a distillation column and the condenser arc at a pressure of 20(psia). The liquid on the top tray is an equimolar mixture of n-butane and n-pentane. The vapor from (he top (ray. assumed to be in equilibrium with the liquid, goes to the condenser where 50 mol-% of the vapor is condensed. What is the temperature on the top tray? What are the temperature and composition of the vapor leaving the condenser?