Water is frequently disinfected with chlorine gas, forming hypochlorous acid (HOCl), which partially ionizes to hypochlorite and protons (HOCl ↔ OCl− + H+, Ka = 2.9×10−8. The amount of HOCl, which is the actual species that performs the disinfection, depends on the pH. Find the fraction that is hypochlorous acid ([HOCl]/{[HOCl] + [OCl−]}) as a function of pH at pH=6, 8, and 10.
