Disinfecting action of chlorine in chlorination of Water is mainly due to (2018)

CHLORINATION Chlorination is one of the greatest advances in water purification. Chlorine kills pathogenic bacteria, but is has no effect on spores and ceain viruses (e.g., polio, viral hepatitis) except in high doses. Apa from its germicidal effect, chlorine oxidizes iron, manganese and hydrogen sulphide; it destroys some taste and odour- producing constituents; it controls algae and slime organisms; and aids coagulation. Action of chlorine : When chlorine is added to water, there is formation of hydrochloric and hypochlorous acids. The hydrochloric acid is neutralized by the alkalinity of the water. The hypochlorous acid ionizes to form hydrogen ions and hypochlorite ions, as follows :- H2O + Cl2 -t HCI + HOC! HOCI -t H + OCI The disinfecting action of chlorine is mainly due to the hypochlorous acid, and to a small extent due to the hypochlorite ions. Ref:- park; pg num:- 774