Sodium hypochloriteÂ is aÂ chemical compoundÂ with theÂ formulaÂ NaOCl or NaClO, comprising aÂ sodiumÂ cationÂ (+
) and aÂ hypochloriteÂ anionÂ (Ã¢ÂÂ
). It may also be viewed as the sodiumÂ saltÂ ofÂ hypochlorous acid. The anhydrous compound is unstable and may decompose explosively.It can be crystallized as aÂ pentahydrateÂ
2O, a pale greenish-yellow solid which is not explosive and is stable if kept refrigerated.
Sodium hypochlorite is most often encountered as a pale greenish-yellow dilute solution commonly known asÂ liquid bleachÂ or simplyÂ bleach, aÂ household chemicalÂ widely used (since the 18th century) as aÂ disinfectantÂ or aÂ bleaching agent. The compound in solution is unstable and easily decomposes, liberatingÂ chlorine, which is the active principle of such products. Indeed, sodium hypochlorite is the oldest and still most importantÂ chlorine-based bleach.
Its corrosive properties, common availability, and reaction products make it a significant safety risk. In particular, mixing liquid bleach with other cleaning products, such as acids orÂ ammonia, may produce toxic fumes.