NaOCl

Sodium hypochlorite (NaOCl) is an inorganic salt that forms aqueous solutions used primarily as a disinfectant and bleaching agent. In solution it equilibrates with hypochlorous acid (HOCl), a potent oxidizing disinfectant. Commercial household bleach typically contains about 3–6% NaOCl in water, with higher concentrations used for industrial sanitization.

Production is commonly achieved by chlorinating sodium hydroxide: Cl2 + 2 NaOH → NaOCl + NaCl + H2O. In water, the relative amounts of NaOCl and HOCl are governed by pH; HOCl is more effective as a microbicide at near-neutral pH.

Applications include disinfection of drinking water and wastewater, surface sanitization in health care and households, endodontic irrigation in dentistry, pulp and paper bleaching, and sanitation in food processing and swimming pools.

Safety and handling: Solutions are corrosive to skin, eyes, and mucous membranes; they release chlorine gas when acidified or heated. Do not mix NaOCl with acids, ammonia, or organic compounds. Store in cool, dark places in corrosion-resistant containers.

Stability and environmental aspects: NaOCl decomposes with heat, light, and metals, forming sodium chloride and sodium chlorate or oxygen; shelf life is limited. In water treatment residual oxidants react with organics, and proper disposal requires neutralization.