Chlorine dissolves in cold and dilute sodium hydroxide solution to produce sodium hypochlorite, sodium chloride and water:
CI2 + 2NaOH → NaCIO +NaCI +H2O
Note that chlorine soluble in hot and concentrated sodium hydroxide solution will not produce sodium hypochlorite, but will produce sodium chloride, sodium chlorate and water:
3CI2 + 6NaOH → 5NaCI + NaCIO3 +3H2O
Product Features for sodium hypochlorite：
White extremely unstable solid, easy to explode when mixed with organic matter or reducing agent. The aqueous solution is alkaline and slowly decomposes into NaCI, NaCIO3 and O2. It decomposes rapidly when heated and exposed to light, and has strong oxidizing properties.