Benzoic acid is dimerized in non-polar solvents such as benzene. A pictorial representation of a compound X, which dimerizes in the organic phase is given below. X= 2x2 Kdim 2x = X2 X Where, Kdim = [X2l6/[X]; is the equilibrium constant for the dimerization process. The distribution ratio (D) is, [X]. + 2[X2]. Kdim = Dimerization constant = Kp + 2Kdim KB[X] Kp = Partition coefficient [X] D = Distribution ratio 1. Write down an expression for the partition coefficient for the distribution of benzoic acid between water and benzene (assume complete dimerization in the organic phase). II. Derive the above equation for the distribution ratio for the distribution of benzoic acid between water and benzene. III. Calculate the extraction efficiency if a 50 mL portion of 0.025 M aqueous solution of benzoic acid is buffered to a pH of 2, and extracted with 50 mL of hexane. Benzoic acid has pK, of 4.20 and a Kp between water and hexane of 4. Kaim = 0.032 mol-dm? IV. Calculate the extraction efficiency if two 25 mL portions of hexane are used in two successive extractions. V. Comment on the selection of the pH of the medium