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JEE Main 2025 · Chemistry · Carbonyl Compounds, Carboxylic Acids and Amines · medium

Toluene is oxidised with alkaline KMnO4 followed by acidification to A. A reacts with SOCl2 to give B, B with excess NH3 gives C, and C with Br2/KOH…

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Toluene is oxidised with alkaline KMnO4\mathrm{KMnO_4} followed by acidification to A. A reacts with SOCl2\mathrm{SOCl_2} to give B, B with excess NH3\mathrm{NH_3} gives C, and C with Br2/KOH\mathrm{Br_2/KOH} gives D. D is diazotised at 273273 K and coupled with β\beta-naphthol in alkaline medium to give E. E is
  1. A. 4-aminoazobenzene
  2. B. N-phenylbenzamide
  3. C. 1-(phenylazo)naphthalen-2-ol
  4. D. benzenediazonium chloride
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Answer: (C) 1-(phenylazo)naphthalen-2-ol

A = benzoic acid, B = benzoyl chloride, C = benzamide. Hofmann bromamide degradation removes one carbon: C6H5CONH2→C6H5NH2\mathrm{C_6H_5CONH_2}\to\mathrm{C_6H_5NH_2} (D = aniline). Diazotisation with NaNO2/HCl\mathrm{NaNO_2/HCl} at 00-5∘5^\circC gives benzenediazonium chloride, which couples at the 11-position of β\beta-naphthol in alkaline medium, giving the orange-red dye 1-(phenylazo)naphthalen-2-ol (E).
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