Calculate the PH of 0.25mol H2SO4

Ka = 1.9 x 10-5

only have experience with simpler ones like KOH, the H2SO4 is whats confusing me

This problem uses the relationship between Ka and the concentrations of the ions. Calculations are as follows:

1.9 x 10-5 = x^2 / (0.25 - x)

x is very small and the denominator is approximately equal to 0.25. Thus, x is 2.2 x 10^-3

pH = - log (2.2 x 10^-3) = 2.66