The vapor liquid equilibrium relation for an ideal binary system is given by y*A = (αABxA)/[1 + (αAB - 1)xA] Here xA and y*A are the mole fractions of species A in the liquid and vapor, respectively. The relative
volatility (αAB) is greater than unity.
A liquid having the composition found in the first part of the linked answer question, is flash distilled at a steady state to a final liquid mole fraction of 0.25. If αAB is 2.5, the fraction of the feed vaporized is