What is the H3O if the OH- is 4.54 x10-6 M?

The concentration of H3O+ can be calculated using the equation Kw = [H3O+][OH-]. Given that Kw = 1.0 x 10^-14, and [OH-] = 4.54 x 10^-6 M, you can solve for [H3O+] to find that it is approximately 2.2 x 10^-9 M.