Question

$S{O_2}$ acts as:
[This question has multiple correct answers.]
A. bleaching agent
B. oxidising agent
C. reducing agent
D. disinfectant

Answer 1

Hint: Sulfur dioxide is a toxic gas responsible for the smell of burnt matches. The sulfur atom present in the sulfur dioxide has an oxidation state of +4 which means it can either accept electrons to get reduced or can either release electrons to get oxidized. It also has many biomedical and biochemical purposes.

Complete step by step answer:

As the sulfur atom in the sulfur dioxide compound exists in the +4 oxidation state, sulfur dioxide can act as a reducing agent. It is oxidized by halogens to give the sulfuryl halides. The reaction of sulfur dioxide with chlorine gas gives sulfuryl chloride:
\[S{O_2}\; + {\text{ }}C{l_2}\; \to {\text{ }}S{O_2}C{l_2}\]
Sulfur dioxide acts as an oxidising agent in the Claus process, which is conducted on a large scale in oil refineries. Here, sulfur dioxide is reduced by hydrogen sulfide to give elemental sulfur. This process is employed to obtain a pure form of sulfur without any impurities in it. The reaction is as follows:
\[S{O_2} + 2{\text{ }}{H_2}S \to 3S{\text{ }} + 2{H_2}O\]
\[S{O_2}\] exhibits bleaching action due to its reducing property. Due to its reducing property, \[S{O_2}\] removes oxygen from colored substances and thus makes it colorless. The reaction that occurs in this mechanism is as follows:
$SO_3^{2 - }(aq) + [dye - O] \to SO_4^{2 - }(aq) + [dye]$
Sulfur dioxide acts as a disinfectant in various food industries. It is used to kill the microorganisms that might affect the food rigorously and is used to preserve it by applying tiny non-traceable dosages.
Thus, the correct option(s) is /are:
A. bleaching agent
B. oxidising agent
C. reducing agent
D. disinfectant

Note:
The step by step oxidation of sulfur dioxide followed by its hydration (reaction with water) is used in the mass production of sulfuric acid in the chemical laboratories and industries.
\[2S{O_2} + 2{H_2}O + {O_2}\; \to 2{H_2}S{O_4}\]