Aliquid mixture contains 50 mol% ethanol in water and a very small amount of non-volatile impurities. it has been proposed to concentrate and purify the alcohol by stripping the ethanol from solution with an available supply of superheated steam. the solution will flow downward in a bubble-cap column counter-current to the upward flowing steam. the feed enters at 70f and the steam at 350f and 1 atm.

(a) calculate the maximum ethanol concentration in the overhead vapour that can be obtained with an infinite number of equilibrium stages

(b) what ethanol concentration and recovery in the vapour will be obtained with a column equivalent to five equilibrium stages with a steam to ethanol feed ratio of 1: 2 (mol/mol)?