 Production of household bleach

Household bleach mainly contains sodium hypochloride, NaOCl (eau de Javel). It is an unstable white powder that dissolves in water to give a yellow stable solution.

It also contains small amounts of NaoH, $H_2{O}_2$ and $Ca(OCl{)}_2$. The first method of producing bleach involved a reaction between chloride gas $C{l}_2$ and sodium carbonate ($N{a}_{2}C{O}_3$). Later, sodium carbonate was replaced by caustic soda (soda lye), NaOH, a cheaper substance that also made the production more efficient.

In this reaction, $C{l}_2(g)$ is reaction with a solution of NaOH giving a spontaneous reaction:

The raw materials of the reaction, chloride and caustic soda come from the electrolysis of brine.