Drugs & Medication

Hypochlorous acid
General
Systematic name	hypochlorous acid
Molecular formula	HClO
Molar mass	52.46 g/mol
Appearance	colorless aqueous solns
CAS number	[7790-92-3]
Properties
Solubility in water	soluble
Other solvents	Et2O, CH2Cl2
Acidity (pKa)	7.53
Hazards
MSDS	External MSDS
Main hazards	oxidizer
Related compounds
Other anions	NaOCl
Other cations	HOBr, HOF
Related compounds	Cl2 Ca(OCl)2
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Hypochlorous acid is a weak acid with the chemical formula HOCl. It forms when chlorine dissolves in water. It cannot be isolated in pure form due to rapid equilibration with its precursor (see below). HOCl is used as a bleach, an oxidizer, a deodorant, and a disinfectant.

Contents 1 Formation 2 Chemical reactions 3 Uses 4 Safety 5 External links 6 References

Formation

Addition of chlorine to water gives both hypochlorous acid and hydrochloric acid (HCl):

Cl₂ + H₂O → HClO + HCl

Chemical reactions

In aqueous solution, hypochlorous acid partially dissociates into the hypochlorite anion ClO^- (also known as the chlorate(I) anion) and the proton H⁺. The salts of hypochlorous acid are also called hypochlorites. One of the best known hypochlorites is household bleach, sodium hypochlorite, NaClO.

In the presence of sunlight, hypochlorous acid decomposes into more hydrochloric acid and oxygen, so this reaction is sometimes seen as:

2Cl₂ + 2H₂O → 4HCl + O₂

HClO is considered to be a stronger oxidant than chlorine.

Uses

In organic synthesis, HOCl converts alkenes to chlorohydrins.^[1]

In biology, hypochlorous acid is thought to be produced by neutrophils to kill bacteria, and it is the active sanitizer in all chlorine-based swimming pool products.

Safety

HOCl is a strong oxidant and thus can form explosive mixtures, and it can give off toxic chlorine gas.

External links

• National Pollutant Inventory - Chlorine

References

1. ^ Unangst, P. C. "Hypochlorous Acid" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.