Potassium hypochlorite

Potassium hypochlorite is a chemical compound with the chemical formula KOCl, also written as KClO. It is the potassium salt of hypochlorous acid. It consists of potassium cations (K+) and hypochlorite anions (−OCl). It is used in variable concentrations, often diluted in water solution. Its aqueous solutions are colorless liquids (light yellow when impure) that have a strong chlorine smell. It is used as a biocide and disinfectant.

Preparation
Potassium hypochlorite is produced by the disproportionation reaction of chlorine with a solution of potassium hydroxide:
 * Cl2 + 2 KOH → KCl + KOCl + H2O

This is the traditional method, first used by Claude Louis Berthollet in 1789.

Another production method is electrolysis of potassium chloride solution. With both methods, the reaction mixture must be kept cold to prevent formation of potassium chlorate.

Uses
Potassium hypochlorite is used for sanitizing surfaces as well as disinfecting drinking water. Because its degradation leaves behind potassium chloride rather than sodium chloride, its use has been promoted in agriculture, where addition of potassium to soil is desired.

History
Potassium hypochlorite was first produced in 1789 by Claude Louis Berthollet in his laboratory located in Javel in Paris, France, by passing chlorine gas through a solution of potash lye. The resulting liquid, known as "Eau de Javel" ("Javel water"), was a weak solution of potassium hypochlorite. Due to production difficulties, the product was then modified using sodium instead of potassium, giving rise to sodium hypochlorite, widely used today as a disinfectant.

Safety and toxicology
Like sodium hypochlorite, potassium hypochlorite is an irritant. It can cause severe damage on contact with the skin, eyes, and mucous membranes. Inhalation of a mist of KOCl can cause bronchus and lung irritation, difficulty breathing, and in severe cases pulmonary edema. Ingestion of strong concentrations can be lethal. Symptoms of contact or inhalation can be delayed.

Potassium hypochlorite is not considered to cause a fire or explosive hazards by itself. However, it can react explosively with numerous chemicals, including urea, ammonium salts, methanol, acetylene, and many organic compounds. Heating and acidification can produce toxic chlorine gas. Containers may explode upon exposure to heat. Potassium hypochlorite forms highly explosive NCl3 upon contact with urea or ammonia.