Calculate the [h3o+] of the following polyprotic acid solution: 0.135 M H2CO3

Answer 1

k1 and k2 are far enough apart in H2CO3 that k2 can be ignored; therefore, treat this as a monoprotic acid with just k1.
H2CO3 ===> H^+ + HCO3^-

k1 = (H^+)(HCO3^-)/(H2CO3)
Set up an ICE chart, substitute into k1 and solve for H^+.