A saturated-liquid mixture of benzene and toluene containing 50 mol% benzene is distillated in an apparatus consisting of a still pot, one theoretical plate, and a total condenser. The still pot is equivalent to one equilibrium stage, and the pressure is 101 kPa. The still is supposed to produce a distillate containing 75 mol% benzene. For each of the following procedures, calculate, if possible, the number of moles of distillate per 100 moles of feed. Assume a relative volatility of 2.5.

(a) No reflux with feed to the still pot. 4:

(b) Feed to the still pot, reflux ratio L/D = 3.

(c) Feed to the plate with a reflux ratio of 3.

(d) Feed to the plate with a reflux ratio of 3. However, in this case, a partial condenser is employed.

(e) Part (b) using minimum reflux.

(f) Part (b) using total reflux