What is the molarity of OH- in an aqueous solution that is 0.17 M HClO4?
(H^+) = (HClO4)
Then (H^+)(OH^-) = Kw = 1E-14
You know H^+ from 1 and you know Kw, solve for OH^-
Then (H^+)(OH^-) = Kw = 1E-14
You know H^+ from 1 and you know Kw, solve for OH^-