Hypochlorite

Hypochlorite refers to chemical species derived from chlorine in the +1 oxidation state, including the hypochlorite ion (ClO−) and its salts such as sodium hypochlorite (NaOCl) and calcium hypochlorite (Ca(OCl)2). In aqueous solution, hypochlorite is a strong oxidizer and is widely used for disinfection and bleaching. In water, hypochlorite is in equilibrium with hypochlorous acid (HOCl): ClO− + H+ ⇌ HOCl. HOCl is the more effective antimicrobial agent; the relative amounts of HOCl and OCl− depend on pH, with HOCl predominating at lower pH and OCl− at higher pH, affecting disinfection efficiency.

Production and uses: Sodium hypochlorite is produced by reacting chlorine with sodium hydroxide or by electrolysis of brine. Calcium hypochlorite is produced by reacting chlorine with calcium hydroxide. These compounds are common household bleaches and are widely used for water treatment, pool sanitation, paper and textile bleaching, and surface disinfection.

Safety and environmental considerations: Hypochlorite releases chlorine gas if mixed with acids, which is highly toxic. It can decompose, especially on heating or in the presence of heavy metals, forming chlorates or releasing oxygen. It can react with organic matter to form potentially harmful disinfection byproducts. Storage and handling require ventilation, avoidance of ammonia and acids, and protection from heat and light. In the environment, hypochlorite rapidly degrades to chloride.