Nicotine is extracted from an aqueous solution at a flow rate of 1000 kg/st containing 2.5% nicotine by weight, and kerosene at a flow rate of 1500 kg/st containing 0.05% by weight of nicotine in a countercurrent single-stage extraction system. If 85% of the nicotine in the feed is separated by the extract phase, find the mole fraction of nicotine in the raffinate phase. It will be assumed that the solvents do not mix at all.

a) 0.00373

b) 0.00383

c) 0.00403

d) 0.00393