JEE Chemistry 2025 Question with Solution

Given: A substituted aromatic nitro compound is subjected to Sn/HCl, then NaNO2, HCl, 273 K, and finally C2H5OH. Find: The products A and B.

From the solution, the key idea is that the nitro group is first reduced to an amine, and the amine then undergoes diazotization. The solution explicitly states that the correct option is C.

The reaction path is:

1. Sn/HCl reduces the nitro group to an aromatic amine.
2. NaNO2/HCl at 273 K converts the amine into the corresponding diazonium salt.
3. Treatment with ethanol reduces the diazonium group, replacing it by hydrogen, while ethanol is oxidized to acetaldehyde.

Therefore, the final organic product is bromobenzene, and the accompanying oxidation product is acetaldehyde.

The correct option is C.

Given: The sequence involves reduction of a nitro compound, diazotization, and reaction with ethanol. Find: Which option matches the final products.

Identify principle:

• Nitro compounds on an aromatic ring are reduced by Sn/HCl to amines.
• Aromatic amines on treatment with NaNO2/HCl at 273 K form diazonium salts.
• Diazonium salts with ethanol undergo replacement of the diazonium group by hydrogen.

Apply transformation logic:

• Nitro-substituted aryl bromide  aryl amine
• Aryl amine  aryl diazonium salt
• Aryl diazonium salt  aryl bromide framework with the diazonium position replaced by hydrogen
• Ethanol is converted to CH3CHO during this process

Verify with options:

• the solution states Product 3: Correct.
• Hence the matching pair is bromobenzene and CH3CHO.

Therefore, the correct option is C.