Question

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

Answer 1

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