Problems 6 and 7 are based on the following information: Acetic acid is to be extracted from an aqueous solution by counter-current extraction with isopropyl ether. The feed is 10,000 kg/hr of 28% acetic acid.

6. The number of equilibrium stages required for a solvent feed rate of 3.0,000 kg/hr and an extract composition of 8% acetic acid is (a. 4 b. 5 c. 8 d. 1.0)

7. The minimum solvent to feed ratio which will give the. same raffinate composition is ( a. 3.14 b. 4.3 c. 2.4 d. 1.75)

Please provide a detailed solution. Thank you!