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JEE Advanced levelSingle correct optionDifficulty 3 of 3nc215

Aniline is first converted into acetanilide, nitrated (major product para), hydrolysed, then diazotised with / dil. at 273-278 K, and the diazonium salt is added to an alkaline solution of 2-naphthol. The dye (Para Red) is

  1. A3-[(4-nitrophenyl)diazenyl]naphthalen-2-ol
  2. B1-[(2-nitrophenyl)diazenyl]naphthalen-2-ol
  3. C1-[(3-nitrophenyl)diazenyl]naphthalen-2-ol
  4. D1-[(4-nitrophenyl)diazenyl]naphthalen-2-ol

Answer: D

Acetanilide is nitrated mainly at the para position, and hydrolysis gives 4-nitroaniline. Diazotisation gives 4-nitrobenzenediazonium chloride (a more reactive electrophile because of the nitro group), which couples at position 1 of 2-naphthol. The product is 1-[(4-nitrophenyl)diazenyl]naphthalen-2-ol.
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