Question

Bleaching powder in cold water is an excellent bleaching agent. But it cannot act as a good bleaching agent when dissolved in hot water.Why?

Answer 1

Bleaching powder reacts with cold water to produce chloride and hypochlorite ions. Hypochlorite ions dissociate producing nascent oxygen Which is responsible for bleaching
`CaOCL_2+H_2O rarrCa^(+2)+Cl^(-)+ClO+H^++OH^-`
Bleaching powder reacts with hot water and produces chloride and chlorate ions
`3ClO^(-)rarr2Cl^(-)+ClO^-`