Given a diprotic acid H2A, with two ionoization constants ka1 = 4.09x10^-4 and ka2 = 4.00x10^-11, calculate the pH and molar concentrations of H2A, HA- and A2- for each of the solutions below:
a) 0.116 M solution of H2A
b) 0.116 M solution of NaHA
c) 0.116 M solution of Na2A