Question

Baeyer's reagent is used in the laboratory for:
A. Detection of glucose
B. Reduction process
C. Detection of benzene
D. Detection of double bond

Answer 1

First we should be aware with the molecule of the given Bayer's reagent. Now we know that the reagent is the hot alkaline solution of $KMn{O_4}$. Now we know that we know what exactly is the reagent then we can get to the working of the molecule which is the detection of the double and triple bonds in the solution which also signifies the detection of unsaturation.

Complete step by step answer:
Here in the given question statement the question is regarding the nature and the role of the baeyer's reagent in organic chemistry. Now we first have to know what exactly is the Baeyer's reagent, so we can get the brief idea and then we can get to the working of the compound and then we can get the answer.
So let's do the answer step by step.
First of all we need to make sure that though Bayer's reagent technically is potassium permanganate, it is not just a normal one. The Baeyer's reagent is an alkaline solution of cold $KMn{O_4}$ when used as a reagent. Here reagent signifies the catalytic role of the compound.
It is mostly referred to as Bayer's reagent as it is named after the German organic chemist named Adolf von Baeyer.
Now regarding the working of the reagent we get that the reaction with double or triple bonds $\left( { - C = C - {\text{ }}or{\text{ }} - C \equiv C - } \right)$ is capable of causing the color to fade from purplish-pink to brown. This is the definitive nature of the compound.
So moreover we can say that Bayer's reagent is an alkaline solution of cold $KMn{O_4}$ which is commonly used in the detection of the trace of unsaturation in the molecule in which it is tested.

Hence the correct answer is option D.

Note: A major application of is as a reagent for the synthesis of organic compounds. Significant $KMn{O_4}$ amounts are required for the synthesis of ascorbic acid, chloramphenicol, saccharin, isonicotinic acid, and pyrazinoic acid. Potassium permanganate can be used to quantitatively determine the total oxidizable organic material in an aqueous sample.