Question

(a) What is bleaching powder? How is bleaching powder prepared? Write chemical equation of the reaction involved in the preparation of bleaching powder.
(b) What happens when bleaching powder reacts with dilute sulphuric acid? Give equation of the reaction involved.
(c) State two important uses of bleaching powder.

Answer 1

1. Bleaching powder is calcium oxychloride (CaOCl₂) and is also called chloride of lime.

Preparation:
Bleaching powder is prepared by passing chlorine gas over dry slaked lime.

Ca(OH)₂ + Cl₂ → CaOCl₂ + H₂O
(Slaked lime)

2. When bleaching powder reacts with dilute sulphuric acid, all the chlorine present in it is liberated. This chlorine acts as a bleaching agent.

​​CaOCl₂ + H₂SO₄ → CaSO₄ + Cl₂ + H₂O

c. Uses:
i. Bleaching powder is used in making chloroform (CHCl₃).
ii. It is used as an oxidising agent in many chemical industries.