Question

Bleaching action of $ {\text{CaOC}}{{\text{l}}_{\text{2}}} $ is due to:
(A) Nascent oxygen
(B) $ {\text{Ca}} $
(C) $ {\text{Cl}} $
(D) $ {\text{HCl}} $

Answer 1

Hint: $ {\text{CaOC}}{{\text{l}}_{\text{2}}} $ is known as calcium oxychloride and it is commonly known and used as bleaching powder. The main function of bleaching powder is to remove colors and stains from fabrics and other material. Bleaching action is observed due to oxidation. To answer this question, you must recall the dissociation of bleaching powder and identify the strong oxidising agents responsible for its bleaching action.

Complete step by step solution:
First bleaching powder is treated with dilute acids in excess quantities on which it undergoes dissociation to form chlorine gas. Chlorine on reaction with water produces nascent oxygen.
 $ {\text{CaOC}}{{\text{l}}_{\text{2}}} + {\text{HCl}} \to {\text{CaOH}} + {\text{C}}{{\text{l}}_2} $
 $ {\text{C}}{{\text{l}}_2} + {{\text{H}}_2}{\text{O}} \to {\text{HCl}} + {\text{HClO}} $
 $ {\text{HClO}} \to {\text{HCl}} + \left[ {\text{O}} \right] $
The nascent oxygen produced combines with the coloured substances present on or in the material and causes its oxidation to form colorless substances thus removing the undesirable stains. Chlorine is known as a very strong oxidizing agent in the presence of moisture, as it forms nascent oxygen. Nascent oxygen is a monatomic radical of oxygen which is highly oxidative and very reactive. Thus, the cleaning action of bleaching powder or calcium oxychloride is due to the nascent oxygen and chlorine.
Thus, the correct answers are A and C.

Note:
Bleaching powder is primarily used for the bleaching of stained or dirty clothes as a bleaching agent for cotton fabrics in the textile industry. Also due to its strong oxidizing properties, it is also used as an oxidizing agent in many industries. It also finds applications as a disinfectant for water for making portable water, due to the release of chlorine which is a strong disinfectant.