We wish to remove acetic acid from water with benzene at 40C, at which the distribution coefficient is 0.1022 in weight fraction units. The inlet water contains 2.0 wt% acetic acid with a total flowrate of 250 kg/h. The inlet benzene is pure with a flowrate of 3000 kg/h. We want the outlet water stream to have less than 0.05 wt% acetic acid. Assume dilute streams with negligible flowrate changes.

a. What is the minimum benzene mass flowrate?

b. How many stages are needed?

c. What is the outlet weight percent of acetic acid in the benzene stream?