Afractionating column is operating at 1 atmosphere pressure to produce a reflux and distillate product containing 90 wt% ethanol and the balance water, and a bottoms product containing 1.0 wt% ethanol. the feed contains 35 wt% ethanol and is introduced at 183.4 of at a rate of 1,000 lb/hr. reflux is returned to the top plate of the column at a rate of 1170 lb/hr. (a) how many actual plates (in addition to the still) are required with an overall plate efficiency of 70 per cent? assume the still equivalent to one ideal plate. (b) what are the rates of heat transfer in the still and in the condenser? (c) at what rate does vapour leave the still, and what is its composition? (d) to the downspout of which actual plate should the feed be introduced? assume equal plate efficiencies in the stripping and rectifying sections.