Chem help - pH!!!!!!!!!

Question

Calculate the pH of a 0.40 M H2SO3, solution that has the stepwise dissociation constants Ka1 = 1.5 × 10^-2 and Ka2 = 6.3 x 10^-8

a. 2.22

b. 1.15

c. 1.11

d. 1.82

Answer 1

H2SO3 <------> H+ + HSO3-

1.5 x 10^-2 = x^2 / 0.40-x

x = [H+] = [HSO3-] = 0.0703 M ( solving the equation by quadratic formula)

HSO3- <-----> H+ + SO32-

6.3 x 10^-8 = (x + 0.0703)(x) / 0.0703-x

x = 6.3 x 10^-8 M

[H+] = 0.0703 + 6.3 x 10^-8 = 0.0703

pH = 1.15

Ka2 is small and does not affect the [H+]