Question

Bleaching action of bleaching powder is due to:
A: $Cl$
B: $O$
C: $Ca$
D: $C{l_2}$

Answer 1

Hint: Bleach is the generic name of any chemical substance which is used to remove stains or color in a process called bleaching. It is a dilute solution of sodium hypochlorite. $Ca{\left( {ClO} \right)_2}$ is a chemical formula of sodium hypochlorite.

Complete step by step answer:
We know the chemical name of bleaching powder is sodium hypochlorite. Its molecular formula is $Ca{\left( {ClO} \right)_2}$. The calcium hypochlorite is a white solid. Sodium hypochlorite is termed as liquid bleach. Calcium hypochlorite is relatively more stable than sodium hypochlorite and contains more chlorine. Calcium hypochlorite is available in two forms: hydrous and anhydrous. It is used as a disinfectant for drinking water and to sanitize swimming pools. In pools, sodium hypochlorite is usually preferred because if we use calcium hypochlorite calcium residue may remain in the water. Calcium hypochlorite is an oxidizing agent used in organic chemistry. It is used in the production of chloroform. When it reacts with water it produces nascent oxygen. This reaction is written below:
$2CaOC{l_2} + 2{H_2}O\underset {} \leftrightarrows CaC{l_2} + Ca{\left( {OH} \right)_2} + 2HClO$
$HClO\underset {} \leftrightarrows HCl + \left[ O \right]$
$\left[ O \right]$ is nascent oxygen. This is the oxygen that is prepared freshly in a chemical reaction. It refers to monatomic oxygen. This nascent oxygen is responsible for bleaching action. This oxygen reacts with colored material and makes that material colorless. This means the bleaching action of bleaching powder is due to nascent oxygen.

So the correct answer is option B that is $O$.


Note:
Nascent gases are produced during a chemical reaction. These gases are more reactive than the gases which are present naturally and stored for a period of time. These gases are basically monatomic gases. This means they are made up of a single atom only.