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11. A feed mixture having a composition of 40 mol\% n-butane, 40mol%n-pentane, 15 mol\% n-hexane and 5 mol\% n-heptane is to be fractionated in a distillation column at 405.3kPa so that 95mol% of the n-pentane is recolvered in the distillate and 95mol% of the n-hexane in the bottoms. The liquid feed at the boiling point is fed to the column at a flow rate of 1,000mol/h. a. Calculate the flow rates and the compositions of distillate and bottoms. [12 marks] b. Show that the boiling point of the feed is 74C. [8 marks]