benzene and hexane are being considered as solvents to extract acetic acid from aqueous mixtures. at a certain temperature, distribution coefficients are: 0.096 ( benzene)/( water) and 0.0221 ( hexane)/( water). a stream containing 100 kg of aqueous solution is fed with 0.3 mass fraction acetic acid to be reduced to 0.081 mass fraction acetic acid. find the mass in kg of solvent required if hexane is used or if benzene is used.