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

(a) Bleaching powder is Calcium oxychloride ($CaOC{l}_2$). It is prepared by passing chlorine gas over dry slaked lime.

Reaction: $Ca(OH{)}_2+C{l}_2\to CaOC{l}_2+H_{2}O$

(b) When bleaching powder reacts with dilute sulphuric acid, it produces chlorine gas.

Reaction: $CaOC{l}_2+H_{2}S{O}_4\to CaS{O}_4+C{l}_2\left(g\right)+H_{2}O\left(l\right)$

(c) Two important uses of bleaching powder are-

(i) It is used for disinfecting the drinking water supply.

(ii) It is used in the manufacture of chloroform.