Question

Describe the manufacturing of bleaching powder. Why does it lose its activity on long storage?

Answer 1

Manufacturing of bleaching powder:

1. The formula of bleaching powder is $Ca{\left(OCl\right)}_2$.
2. It is prepared by the chlor-alkali process.
3. In this process chlorine gas is passed over calcium hydroxide, and then calcium hypochlorite is formed along with the formation of water.
4. The reaction involved is: $Ca{\left(OH\right)}_2+C{l}_2\to Ca{\left(OCl\right)}_2+H_{2}O.$

When bleaching powder is stored for a longer time, it breaks into salt and calcium chlorate, and it is soluble in water. Therefore, it becomes water and simple salt, and it does not contain any free chlorine molecules.