Question

Predict the products formed when cyclohexane carbaldehyde reacts with the following reagents.
Semicarbazide and weak acid

Answer 1

Hint: The structure of cyclohexane carbaldehyde is as follows.

- The structure of semicarbazide is as follows.

In the structure of the semicarbazide there are three amines, out of those three amines two amines are in resonance with carbonyl carbon and amine (terminal) is free from resonance.

Complete answer:
- In the question it is given that to find the products formed when cyclohexane carbaldehyde reacts with semicarbazide and a weak acid.
- We have to find the products when cyclohexane carbaldehyde reacts with semicarbazide and a weak acid.
- The chemical reaction of cyclohexane carbaldehyde with semicarbazide in presence of a weak acid is as follows.

- In the above reaction cyclohexane carbaldehyde reacts with semicarbazide in presence of a weak acid (pH = 3.5) and forms a product called Cyclohexane carbaldehyde Semicarbazone.

- Therefore the product formed is Cyclohexane carbaldehyde Semicarbazone and water.

Additional information:
- The reaction between cyclohexane carbaldehyde and semicarbazide is only possible in acidic conditions.
 - There is a need for a weak acid (pH = 3.5) to make the reaction occur, in basic conditions the reaction does not happen.

Note: Generally in semicarbazide there are three amines. Out of those three amines one amine is not in resonance with the carbonyl group and it is going to act as a nucleophile. The amine which is not in resonance with the carbonyl group in semicarbazide is going to initiate the reaction.