Hypochlorous acid is a weak acid with the chemical formula HClO. It forms when chlorine dissolves in water, and it is HClO that actually does the disinfection when chlorine is used to disinfect water for human use. It cannot be isolated in pure form due to rapid equilibration with its precursor. HClO is an oxidizer, and as its sodium salt sodium hypochlorite, (NaClO), or its calcium salt calcium hypochlorite, (Ca(ClO)₂) is used as a bleach, a deodorant, and a disinfectant.