When chlorine reacts with water, what disinfectant is formed?

When chlorine reacts with water, it primarily forms hypochlorous acid, which is a powerful disinfectant. This occurs through a chemical reaction where chlorine (Cl2) dissolves in water to produce a mixture of hypochlorous acid (HOCl) and hydrochloric acid (HCl). Hypochlorous acid is effective at killing bacteria, viruses, and other pathogens, making it a vital component in pool sanitation and water treatment processes.

While sodium chloride and calcium chloride are associated with chlorine and can be present in the water, they are not the primary disinfectant created through the reaction of chlorine with water. Sodium chloride may be formed if the water contains chlorides, and calcium chloride can result from reactions involving calcium, but these do not play a role in direct disinfection. Therefore, hypochlorous acid stands out as the correct and most significant disinfectant produced in this chemical reaction.