Chapter 9.5, Problem 9.20P

Calculate the value of ${\text{[H}}_{\text{3}}{\text{O}}^{\text{+}}\text{]}$ from the given ${\text{[OH}}^{\text{-}}\text{]}$ in each solution and label the solution asacidic or basic:
$(a)[{\text{OH}}^{\text{-}}]\text{ = }{10}^{-6}\text{M; }(b)[{\text{OH}}^{\text{-}}]\text{ = }{10}^{-9}\text{M; }(c)[{\text{OH}}^{\text{-}}]\text{ = }5.2\times {10}^{-11}\text{M; }(d)[{\text{OH}}^{\text{-}}]\text{ = }7.3\times {10}^{-4}\text{M}\text{.}$