Calculate the pH of the following aqueous solution:

1.00 mol/L sulfuric acid, H2SO4(aq)

1 answer

H2SO4 is one of those acids that is 100% ionized for the first H^+ and less than 100% for the second one.
H2SO4 ==> H^+ + HSO4^- 100%
HSO4^- ==> H^+ + SO4^= not 100%

(H^+) = 1.00 M for the first ionization.
The second one is guided by k2.
k2 = (H^+)(HSO4^-)/(HSO4^-)
Plug into k2 as follows:
(H^+) = 1.00 + x
(SO4^=) = x
(HSO4^-) = 1.00 - x
Solve for x.
Post your work if you get stuck. This is a quadratic you must solve BUT it may be easier to use approximations. You will need to look up k2 for H2SO4.