Q.2. Crude oil containing 5.0 mole per cent of gasoline is stripped by running the crude down a column up which live steam is passed, so that 15 kmol of steam are used/100 kmol of oil stripped. Determine the number of theoretical plates required to reduce the gasoline content to 0.05 mole per cent, assuming that the crude oil is non-volatile. The vapour-liquid relation of the gasoline in the oil is given by yo = 44x, where yo is the mole fraction in the vapour and x the mole fraction in the liquid. The temperature is maintained constant by internal heating, so that steam does not condense in the tower