Q43 / 150 · MHT CET 2026 (11 April Shift 1) · Chemistry
Which of the following reactions is an example of a disproportionation reaction?
- AWolf-Kishner reduction.
- BAldol condensation.
- CClemmenson reduction.
- Correct answerDCannizzaro reaction.
Solution
A disproportionation reaction is a redox reaction in which the same substance undergoes both oxidation and reduction simultaneously.
In the Cannizzaro reaction, aldehydes lacking $\alpha$-hydrogens undergo self-oxidation and self-reduction in the presence of a concentrated base.
One molecule of the aldehyde is reduced to the corresponding alcohol, while another molecule is oxidized to the salt of the corresponding carboxylic acid.
For example: $2HCHO + NaOH \rightarrow HCOONa + CH_3OH$
Here, formaldehyde is oxidized to sodium formate and reduced to methanol. Thus, the Cannizzaro reaction is an example of a disproportionation reaction.
Wolf-Kishner and Clemmensen reductions are purely reduction reactions, whereas Aldol condensation is a condensation reaction.
Answer: Cannizzaro reaction.
In the Cannizzaro reaction, aldehydes lacking $\alpha$-hydrogens undergo self-oxidation and self-reduction in the presence of a concentrated base.
One molecule of the aldehyde is reduced to the corresponding alcohol, while another molecule is oxidized to the salt of the corresponding carboxylic acid.
For example: $2HCHO + NaOH \rightarrow HCOONa + CH_3OH$
Here, formaldehyde is oxidized to sodium formate and reduced to methanol. Thus, the Cannizzaro reaction is an example of a disproportionation reaction.
Wolf-Kishner and Clemmensen reductions are purely reduction reactions, whereas Aldol condensation is a condensation reaction.
Answer: Cannizzaro reaction.
Hence, the correct answer is option: 'D'.