(a) What is the pH of a 6.1 ✕ 10-5 M Ca(OH)2 solution?
(b) What is the H3O+ concentration of the solution?
I already know the answer to part A, I just don't understand how you could use that information to find the concentration of H30+ when its not in the ionic equation.
You don't remember that
(H3O^+)(OH^-) = Kw = 1E-14?
You know OH and Kw, solve for H3O^+