What type of reaction is exemplified by the formation of bleach from chlorine and sodium hydroxide?

The formation of bleach from chlorine and sodium hydroxide is a clear example of a disproportionation reaction. In this type of reaction, a single substance is simultaneously oxidized and reduced.

In the case of bleach production, chlorine gas (Cl2) reacts with sodium hydroxide (NaOH) to form sodium hypochlorite (NaClO), water, and sodium chloride (NaCl). In this process, one chlorine atom in Cl2 is oxidized to form the hypochlorite ion (ClO⁻), while the other chlorine atom is reduced to form the chloride ion (Cl⁻).

This simultaneous occurrence of oxidation and reduction involves the same element undergoing both processes, which is the hallmark of a disproportionation reaction. As such, this makes the right choice regarding the type of reaction that occurs in the formation of bleach from chlorine and sodium hydroxide.