Chapter 16, Problem 16.153MP

In the case of very weak acids, ${\text{[H}}_{\text{3}}{\text{O}}^{\text{+}}]$ from the dissoc iation of water is significant compared with ${\text{[H}}_{\text{3}}{\text{O}}^{\text{+}}]$ from the dissociation of the weak acid. The sugar substit ute saccharin ${\text{(C}}_{\text{7}}{\text{H}}_{\text{5}}{\text{NO}}_{\text{3}}\text{S),}$ for example, is a very weak acid having $K_a=2.1\times {10}^{-12}$ and a soluhility in water of 348 mg/I00 mL. Calculate ${\text{[H}}_{\text{3}}{\text{O}}^{\text{+}}]$ in a saturated solution of saccharin. (Hint: Equilibrium equations for the dissociat ion of saccharin and water must he solved simultaneously.)