Why is sodium hypochlorite in bleach

physical and chemical properties

LookWhiteMelting point decomposed
odortypically after chlorineboiling point decomposed
molar mass74.44 g / molDensity (° C)1.2 g / cm3
Condition at 20 ° CfirmlySolubility in water (0 ° C)
Solubility in water (23 ° C)
29.3 g / 100 ml
96 g / 100 ml

Manufacture and application

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

It is used as an oxidizing agent, e.g. to destroy dyes as a bleaching agent and to detoxify cyanides as well as in the field of disinfection, e.g. also for chlorinating drinking water and swimming pool water.

Environmental impact and health

Develops toxic chlorine gas with acids. Reacts with light metals, chlorine is released on contact with oxidizing agents. Dangerous reactions: The anhydrous salt is explosive. Sodium hypochlorite is a water-polluting substance with the classification WGK 2.

Wastewater treatment / drinking water treatment

Sodium hypochlorite in wastewater leads, among other things, to the formation of poorly degradable AOX compounds. In Appendix 40 (metal processing) of the Waste Water Ordinance, it is advised to detoxify cyanides without the use of sodium hypochlorite.