10. A continuous rectifying column handles a mixture consisting of 40 per cent of benzene
by mass and 60 per cent of toluene at the rate of 4 kg/s, and separates it into a product containing 97 per cent of benzene and a liquid containing 98 per cent toluene. The feed is liquid at its boiling-point.
(a) Calculate the mass flows of distillate and waste liquor.
(b) If a reflux ratio of 3.5 is employed, how many plates are required in the rectifying
part of the column?
(c) What is the actual number of plates if the plate-efficiency is 60 per cent?