Bleaching Powder

The white powder which is generally sprinkled to disinfect any place which is not clean is also used to disinfect water. You must have experienced the typical strong odour from well water during rainy season. The white powder is called bleaching powder and the strong odour is due to chlorine gas which is released when bleaching powder is added to water. When dry slaked lime reacts with chlorine gas, it forms bleaching powder Ca(OH)2(S) + Cl2(g) ----> CaOCl2(s) + H2O(l) When bleaching powder comes in contact with atmospheric CO2 gas, it forms CaCO3(S) and Cl2(g). This Cl2(g) helps in the bleaching action on cotton in the textile industry, wood pulp in paper factories and washed clothes in laundry. Bleaching powder acts as an oxidizing agent in many chemical reactions and is useful in preparation of organic solvent chloroform which is also used as an anesthetic. Bleaching powder is also known as chloride of lime and the chlorine generated is known as "available chlorine" The bleaching powder brands available in market are classified on the basis of percentage of available chlorine present in them. To be continued . . . . .