Question

Malic acid is a diprotic acid with K1 = 3.5 x 10-4 K2 = 7.9 x 10-6

We can represent H2A = A2- + 2H+

Since the Kas are too close in value, we cannot make the assumption that only the first Ka is important. Thus, we can frame this as a combined equilibrium K = K1xK2

With this in mind, use the halfway method to calculate the proton concentration and pH of a 0.000500 M solution of malic acid.

Determine the first four Q values, and report the % H2A that dissociated and the final pH calculated.

Answer 1