Which of the following expressions hold for 0.10 mol/L Na2HA(aq). (HA2- is the doubly-ionized form of H3A, a weak triprotic acid.) (a) [H2A-] = 2 [HA2-] = 3 [A3-] (b) 0.5 [Na+] = [H3A] + [H2A-] + [HA2-]+[A3-] (c) [H+] = [H2A-] + 2 [HA2-] + 3 [A3-] + [OH-] (d) [H+] = [H2A-] + [HA2-] + [A3-] + [OH-] (e) Ka1=[H2A-][H+]/[H3A] (f) Ka2=Kw/Ka1 (g) [H+] + [OH-] = Kw