Activity. In this problem, we calculate the pH of the intermediate form of a diprotic acid, taking activities into account.
(a) Including activity coefficients, derive Equation 9-11 for potassium hydrogen phthalate (K+HP- in the example following Equation 9-12).
(b) Calculate the pH of 0.050 M KHP, using the results in part (a). Assume that the sizes of both HP- and P2- are 600 pm.