The disinfectant action of chlorine is MOSTLY due to which of the following forms?
Hypochlorous acid
Hypochlorite ion
Hydrochloric acid
Both Hypochlorous acid and Hypochlorite ion
The disinfecting action of chlorine is mainly due to the hypochlorous acid, and to a small extent due tothe hypochlorite ions. The hypochlorous acid is the most effective form of chlorine for water disinfection. It is more effective (70-80 times) than the hypochlorite ion. Chlorine acts best as a disinfectant when the pH of water is around 7, because of the predominance of the hypochlorous acid. When pH values exceed 8.5 it is unreliable as a disinfectant because about 90 % of the hypochlorous acid gets ionized to hypochlorite ions.