JEE Main levelSingle correct optionDifficulty 2 of 3nc080
Benzenediazonium chloride is added to a cold alkaline solution of 2-naphthol. The intensely coloured product is
A3-(phenylazo)-2-naphthol
B6-(phenylazo)-2-naphthol
C2-naphthyl phenyldiazenyl ether (O-coupled)
D1-(phenylazo)-2-naphthol, with the azo group at C-1 next to the hydroxyl group
Answer: D
2-Naphthoxide couples at C-1 because attack there keeps the second aromatic ring intact in the intermediate. The azo group therefore ends up on the carbon adjacent to C−OH, giving the orange-red 1-(phenylazo)-2-naphthol.