Question

Bleaching action of ${\text{S}}{{\text{O}}_2}$ is due to:
A. Reduction
B. Oxidation
C. Hydrolysis
D. Acidic nature

Answer 1

Hint: Here, we will proceed by defining bleach agents. Then we will be discussing about the reduction property of sulphur dioxide $\left( {{\text{S}}{{\text{O}}_2}} \right)$ to show that bleaching of ${\text{S}}{{\text{O}}_2}$ is due to reduction.

Complete answer:
Bleaching agents: Bleaching agents are compounds which are used to remove colour from substances such as textiles.
Sulphur dioxide $\left( {{\text{S}}{{\text{O}}_2}} \right)$ is a good reductant. In the presence of water, ${\text{S}}{{\text{O}}_2}$ is able to decolorize substances. Specifically, it is a useful reducing bleach for papers and delicate materials such as clothes.
This bleaching effect normally does not last very long. Oxygen in the atmosphere re-oxidizes the reduced dyes, restoring the colour.
The bleaching of Sulphur dioxide $\left( {{\text{S}}{{\text{O}}_2}} \right)$ is mainly due to its reduction property and its of temporary reaction as soon as it gains required oxygen helps to regenerate its initial property.

Hence, the correct option is A, reduction

Note: Bleaching action of Sulphur dioxide is generally used for bleaching delegate articles like ivory, silk, wool etc. Chlorine, ${\text{C}}{{\text{l}}_2}$ is the permanent bleaching agent which is due to oxidation. The decolorizing action of bleaches is due in part to their ability to remove these electrons which are activated by visible light to produce the various colours.