Why does bleaching powder deteriorate on exposure to air?

Bleaching powder, primarily composed of calcium hypochlorite, deteriorates upon exposure to air due to its reaction with moisture and carbon dioxide present in the atmosphere. This reaction leads to the formation of calcium carbonate and the release of chlorine gas, reducing its effectiveness as a bleaching and disinfecting agent. Additionally, prolonged exposure can result in the breakdown of the hypochlorite ions, further diminishing its potency. Therefore, proper storage in airtight containers is essential to maintain its stability.