Caprolactam is industrially recovered and purified by extraction. A Chemical Engineering student needs to extract acetaldehyde in toluene. A solution of 9.3% acetaldehyde in toluene is to be extracted with water in a six stages co-current unit. If 32.1kg water /100kg feed is used, what is the mass of acetaldehyde extracted and the final concentration? The equilibrium relation is given by: ( kg acetaldehyde/ kg water) =2.27 ( kg acetaldehyde /kg toluene)