Are hypochlorous acid and salt dangerous together

Structural formula
Surname Sodium hypochlorite
other names

Sodium hypochlorite, sodium hypochlorite, chlorine bleach, L'eau de Labarraque / Eau de Javel (aqueous solution)

Molecular formula NaOCl
CAS number 7681-52-9
Brief description yellow solid with an unpleasant, sweet odor[1]
Molar mass 74.44 g mol−1
Physical state firmly
density 1.2 g cm–3 (Solution with 13% free chlorine)[1]
Melting point 24.5 ° C (pentahydrate)
Vapor pressure

23 hPa[1] (20 ° C[1])


good in water (293 g / L at 0 ° C, 942 g / L at 23 ° C, each pentahydrate)

safety instructions
WGK 2 - hazardous to water[1]
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions.

Sodium hypochlorite (NaOCl) is the sodium salt of hypochlorous (outdated also hypochlorous) acid (HClO). It is a white powder that normally contains six moles of crystal water per mole of sodium hypochlorite. The common name of the aqueous solution of sodium hypochlorite is Eau de Labarraque or Eau de Javel, with the designation Eau de Javel strictly speaking, is incorrect. This refers to a solution of potassium hypochlorite, possibly in a mixture with other salts such as potassium chloride; however, there is often no distinction.

Extraction / representation

Sodium hypochlorite is produced by introducing chlorine gas into sodium hydroxide solution or by electrolysis of a sodium chloride solution.

This reaction causes considerable technical problems. Since it is formally a hydrolysis of the chlorine after

with subsequent neutralization of the hydrochloric acid or hypochlorous acid formed in this way, it is easy to see that the reaction enthalpies of these reactions lead to strong warming, to which all hypochlorites are sensitive. In fact, the same chemical process is used to make chlorate, but by reacting in hot solution. For this reason, all technical hypochlorites contain varying, sometimes large amounts of chlorate. The reaction of the hypochlorite formed during production with chlorine ultimately leads to chlorate.


The intended use is bleaching or disinfecting (for example in swimming pools). Use in swimming pools is not without problems, since the quantities to be dosed must be sufficient to chlorinate the ammonia (or amines) present beyond the level of monochloramine, since only then is adequate disinfection guaranteed.

Sodium hypochlorite is also the essential active ingredient in disinfecting and bleaching household cleaners such as DanKlorix and many others. Various mold removers also contain this active ingredient.

Sodium hypochlorite is also used in dentistry. For example, it is used in the root canal treatment of bacterially infected teeth in order to disinfect them.

safety instructions

Extreme caution is required when handling sodium hypochlorite! There is a risk of explosion if sodium hypochlorite reacts with numerous substances and groups of substances, including reducing agents, amines, formic acid, methanol, organic substances and a few others. Strongly attacks the mucous membranes when inhaled.

In addition, sodium hypochlorite reacts very violently with acids (e.g. hydrochloric acid, nitric acid) and oxidizing agents (e.g. hydrogen peroxide, permanganate), generating heat and releasing chlorine gas and / or nitrous gases.

Even heating or sunlight can cause sodium hypochlorite to break down, releasing chlorine, hydrogen chloride, chlorine dioxide and oxygen, among other things. This must also be taken into account when storing the substance.


  1. abcdefGH BGIA GESTIS substance database: 12th of May. 2007

Categories: Corrosive Substance | Environmentally hazardous substance | Sodium compound | Hypochlorite