Textbook Problem

Calculate the pH of a 0.200-M solution of C₅H₅NHF. Hint: C₅H₅NHF is a salt composed of C₅H₅NH⁺ and F⁻ ions. The principal equilibrium in this solution is the best acid reacting with the best base; the reaction for the principal equilibrium is

${\text{C}}_{\text{5}}{\text{H}}_{\text{5}}{\text{NH}}^{\text{+}}\left(aq\right)+{\text{F}}^{-}\left(aq\right)\rightleftharpoons {\text{C}}_{\text{5}}{\text{H}}_{\text{5}}\text{N}\left(aq\right)+\text{HF}\left(aq\right)K=8.2\times {10}^{-3}$