2. If 15 mg/L of HOCI is added to a potable water for disinfection and the final pH is 7.0, what percent of the HOCI remains as the parent acid?

What percent remains if the pH is 8.5? Assume the temperature is 25°C. \text { Reaction: } \quad \text { HOCl } \leftrightarrow \mathrm{H}^{+}+\mathrm{OCl}^{-} \quad \mu \mathrm{K}_{\mathrm{a}}=7.54 \text { at } 25^{\circ} \mathrm{C}