Question

Draw the structure of 2, 4 - dinitrophenylhydrazone of acetaldehyde.

Hint:

2,4-DNP test is a general test for the presence of a carbonyl group (\(C=O\)).

Answer 1

Step 1: Understanding the Concept:
Aldehydes react with 2,4-DNP (Brady's reagent) to form crystalline orange/yellow solids called 2,4-dinitrophenylhydrazones.
Step 2: Detailed Explanation:
This is a nucleophilic addition-elimination reaction. The \(-NH_2\) group of the hydrazine reacts with the \(=O\) of the carbonyl group.
Acetaldehyde is \(CH_3CHO\).
The resulting structure is:
\[ CH_3-CH=N-NH-\text{Benzene Ring with } -NO_2 \text{ at positions 2 and 4} \]
Step 4: Final Answer:
The structure is \( CH_3-CH=N-NH-C_6H_3(NO_2)_2 \).