7.28 (McCabe-Thiele method, number of trays given, Murphree efficiency given 2A distillation column which separates pinene and limonene consists of a reboiler, 15 theoretical plates and a total condenser. The feed is at its bubble point and has 72% pinene in it. The overhead product contains 95 mole\% pinene and the bottom product has 94% limonene. Determine (a) the reflux ratio to be maintained, (b) the location of the feed plate, (c) the number of ideal stages required for the above separation for total reflux. Given: =1.71