In water, they form hypochlorous acid and sodium or calcium salts. Under controlled conditions, the germicidal action of hypochlorites equals that of chlorine gas. Chloramines are formed by a reaction of chlorine with ammoniacal nitrogen in water. In solution, they slowly form hypochlorous acid and organic salts. Chloramines are more stable and less corrosive than hypochlorites, and they have a longer lasting germicidal action.
Chloramines require a long contact time to be effective sanitizing agents.
Very acidic chlorinated water is corrosive to equipment. Very alkaline chlorinated water is also corrosive and has a reduced killing ability. A pH range of 6.0 to 7.5 is recommended for chlorine sanitizing solutions. Organic matter will react with hypochlorous acid, leaving less free chlorine. Since it is the free chlorine that kills bacteria, large amounts of organic matter will reduce the germicidal activity of a chlorine solution.