What is the role of chlorine gas in the preparation of bleaching powder?

Chlorine gas reacts with dry slaked lime (calcium hydroxide) to produce bleaching powder (calcium hypochlorite). The chemical equation for the reaction is: 2Ca(OH)2 + 2Cl2 → Ca(OCl)2 + CaCl2 + 2H2O. Bleaching powder is used extensively for disinfecting drinking water and as a bleaching agent for cotton and linen in the textile industry. It is also used in the paper industry and for manufacturing various chemicals.