See image — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

Concept: Converting an amine (-NH2) directly to a nitro group (-NO2) on a benzene ring requires an oxidizing agent capable of oxidizing the amino group all the way to a nitro group. Step 1: Identify the transformation. Aniline (PhNH2) must be converted to nitrobenzene (PhNO2). This is a net oxidation of the nitrogen from -2 (in NH2) to +3 (in NO2), a significant oxidation. Step 2: Evaluate the reagents. - CF3CO3H (trifluoroperacetic acid) is a powerful peracid and strong oxidizing agent. It is well known to oxidize primary aromatic amines (ArNH2) directly to nitro compounds (ArNO2) via sequential oxidation (ArNH2 → ArNHOH → ArNO → ArNO2). This is a known and reliable synthetic method. - H2SO4 is an acid, not an oxidant capable of oxidizing NH2 to NO2; it would protonate the amine but not oxidize it. - LAH (lithium aluminum hydride) is a strong reducing agent; it would not oxidize NH2 to NO2. - NaBH4 is also a reducing agent; it cannot perform this oxidation. Step 3: CF3CO3H (trifluoroperacetic acid) is the correct oxidant for converting ArNH2 to ArNO2. It is a much stronger peracid than mCPBA or peracetic acid and can achieve full oxidation to the nitro group. Why other options fail: H2SO4 only acts as an acid/dehydrating agent; LAH and NaBH4 are reductants and would reduce rather than oxidize nitrogen. Therefore, the correct answer is A.