Nomenclature
CAS number: 7790-92-3
ClHO; mol wt 52.46.
Cl 67.58%, H 1.92%, O 30.50%.
HClO.
Description and references
Known in aq soln only. Formed by the action
of water on chlorine: Cady, Inorg. Synth. 5, 160 (1957). A 25% soln of hypochlorous acid is obtained
when chlorine hydrate and mercuric oxide are distilled at low pressure:
Goldschmidt, Ber. 52, 753 (1919). Review: J. A. Wojtowicz, “Chlorine Monoxide,
Hypochlorous Acid, and Hypochlorites”, in Kirk-Othmer Encyclopedia of Chemical Technology vol. 5 (Wiley-Interscience, New York, 3rd ed., 1979) pp 580-611.
Properties
Aq soln (25%), greenish yellow liquid. May be
stored for a few days if kept at 20°. Dec slowly to Cl2, O2 and HClO4. Very weak acid. pK (25°) 7.49. Strong oxidizing
agent. When a 25% soln is evapd in a vacuum, chlorine monoxide, Cl2O, is given off. Cl2O in soln with HClO may be
removed by shaking with carbon tetrachloride, but will form again.
Protect from light.Note
An aqueous soln of the potassium salt
is known as
Javelle water or
Eau de Javelle (also used for
sodium hypochlorite,
q.v.).
Use
Disinfectant.