15. Solving a chemistry problem

8. The distribution coefficient of phenol in the system water - octyl alcohol is 31. The volume of the aqueous phase from which phenol is extracted is 100.0 ml. Calculate and compare the degree of extraction of phenol during: a) a single extraction of 5.0 ml of octyl alcohol; b) single extraction with 25.0 ml of octyl alcohol; c) 5-fold extraction with portions of octyl alcohol, 5.0 ml each.
Answer: a) R = 60.8%; b) R = 88.6%; c) R = 99.1%.