Question

Baeyer's reagent is used for the detection of
A. Amines
B. Glucose
C. Unsaturated bond
D. Alcohol

Answer 1

Hint: Baeyer's reagent is the hot alkaline solution of potassium permanganate (\[KMn{O_4}\]). It is utilised for the identification of the double and triple bonds in a solution which is also known as the identification of unsaturation.

Complete Step by Step Solution:
Here, the provided question is asked about the role of the Baeyer's reagent in organic chemistry.
First, we have to know Baeyer's reagent to obtain a better understanding, and then we can know the working of the compound, this would help in obtaining the answer and explanation both.

Baeyer's reagent is an alkaline or basic solution of \[KMn{O_4}\]. It is pinkish-purple in colour.
- It is known as a reagent for its catalytic role.
- It is known as Baeyer's reagent as it is labelled after the German organic chemist Adolf von Baeyer.
- It is a powerful oxidising agent and is utilised in qualitative organic estimation to examine the existence of unsaturation.
- To test a given solution of alkene or alkyne, the solution is first treated with Baeyer's reagent which interacts with it altering its pinkish-purple colour to brown.

The alkene or alkyne is converted to 1,2-diol, while the permanganate is reduced to manganese dioxide (\[Mn{O_2}\]). The brown colour is due to the manganese dioxide.
The reaction happens as follows:

Image: Reaction of ethene with Baeyer's reagent

The reaction is crucial because it doesn't decolorize alkanes or aromatic compounds, and therefore, can be utilised to differentiate them from alkenes and alkynes.
So, Baeyer's reagent is used for the detection of unsaturated bonds.
So, option C is correct.

Note: Potassium permanganate is utilised for no.of skin conditions like fungal infections of the foot, external injuries, dermatitis, and tropical ulcers. It is utilised greatly in the water treatment industry. It is utilised to eliminate iron and hydrogen sulphide from well water. Historically it was utilised to purify drinking water.