See image — Aldehydes Ketones and Carboxylic Acids Chemistry Question

💡 Solution & Explanation

Concept: Clemmensen reduction uses zinc amalgam (Zn(Hg)) in concentrated hydrochloric acid (HCl) to reduce a carbonyl group (ketone or aldehyde) directly to a methylene (CH2) group. The reaction converts C=O to CH2 without forming an alcohol intermediate. Step 1 - Identify the substrate: The starting material is 3-nitroacetophenone (acetyl group -COCH3 at C1, nitro group -NO2 at C3 of benzene ring). Step 2 - Apply Clemmensen reduction: The ketone carbonyl (C=O) in the -COCH3 group is reduced to -CH2-, converting -CO-CH3 into -CH2-CH3 (an ethyl group). The reaction selectively reduces the carbonyl to a methylene under acidic conditions. Step 3 - Fate of the nitro group: Clemmensen reduction is carried out under strongly acidic conditions (HCl), but the zinc amalgam selectively reduces the carbonyl. However, in some contexts Zn/HCl can also reduce nitro groups to amines. In this problem, the given correct answer is C, which shows -NH2 instead of -NO2, meaning the nitro group IS reduced to an amino group under these conditions (Zn/HCl can reduce -NO2 to -NH2). Step 4 - Product: The product has an ethyl group (-CH2CH3) at position 1 and an amino group (-NH2) at position 3, which corresponds to 3-aminoethylbenzene (1-ethyl-3-aminobenzene). Why other options fail: - (a): Keeps -NO2 intact and shows correct reduction of ketone to ethyl, but ignores reduction of nitro group by Zn/HCl. - (b): Shows an alcohol (secondary alcohol -CH(OH)CH3), which is NOT the product of Clemmensen reduction; Clemmensen goes directly to CH2, bypassing the alcohol. - (d): Shows a longer chain alcohol -CH(OH)-CH2-CH3, which is incorrect in both the chain length and functional group. Therefore, the correct answer is C.