A feed of a vapour-liquid mixture of 12 mol% ethyl alcohol in water is distilled continuously at 1 atm. The feed has q = 0.95. The distillate required is 75 mol% alcohol, representing 80% recovery of the alcohol in the feed. A total condenser is used to produce distillate as saturated liquid and a partial reboiler to provide the boilup as saturated vapour. Feed is introduced onto the optimal stage. Vapor–liquid equilibrium data are given in Table Q1 below.