Chapter 14.5, Problem 39PP

Calculate the $\left[{\text{H}}_3{\text{O}}^{+}\right]$ of each aqueous solution with the following [OH ${}^{-}$ ]:
a. coffee, $1.0\times {10}^{-9}\text{M}$  b. soap, $1.0\times {10}^{-6}\text{M}$
c. cleanser, $2.0\times {10}^{-5}\text{M}$  d. lemon juice, $4.0\times {10}^{-13}\text{M}$