What is hypochlorous acid classified as?

Hypochlorous acid is classified as both a disinfectant and a free residual. As a disinfectant, it is effective in killing bacteria, viruses, and other pathogens in water, making it widely used in water treatment processes. Its ability to inactivate microorganisms is a key aspect of its role as a disinfectant.

Additionally, hypochlorous acid exists in equilibrium with its ion, hypochlorite, depending on the pH levels in the water. When chlorination occurs, hypochlorous acid can act as a free chlorine residual that remains in the water after the disinfection process. This residual is important for maintaining ongoing disinfection and protecting against potential recontamination as the water moves through distribution systems.

In contrast, focusing solely on its role as a disinfectant or a residual overlooks its dual functionality and the essential part it plays in ensuring water safety and quality. It is not merely a compound requiring further treatment, but rather an effective and critical component in water treatment systems.