What is the pH of a 050M solution of C2H2O42 Given Ka1 65 x

What is the pH of a 0.50M solution of C2H2O4^2-
Given Ka1: 6.5 x 10^-2
Given Ka2: 6.1 x 10^-5

Answer Choices:
A.) 0.80
B.) 13.26
C.) 13.2
D.) 7.44

We haven\'t learned pka yet and i believe my professor wants the work shown for this problem using the ICE Table method. Could you show the answer using a.) ICE Table Method? B.) pka method? Thanks

Solution

C2H2O4      ----------------> C2HO4- +    H+

0.50                                    0                   0

- x                                    + x                + x

0.50 - x                               x                   x

6.5 x 10^-2 = x^2 / 0.50 - x

x = 0.151

[H+] = 0.151 M

pH = -log (0.151 ) = 0.8

pH = 0.80