This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Social & Preventive Medicine
Which among the following is an active form of chlorination? 
Select and explain. 
A. Hypochlorite ion, B. Hydrogen chloride, C. Hypochlorous acid, D. Chloride ion
C: Hypochlorous acid
Answer: C: Hypochlorous acid 
Explanation: * The disinfecting action of chlorine is predominantly due to hypochlorous acid. * Hypochlorous acid is most effective form of chlorine and it is almost 70-80 times more effective than hypochlorite ions ref : park 21st ed