JEE Main · 2025 · 29 Jan 2025 · Shift 2 · Compounds Containing Nitrogen

Which one of the following reaction sequences will give an azo dye ?

(A)(see structure)
✓ Correct
(B)(see structure)
(C)(see structure)
(D)(see structure)

Answer: (A)

Solution

An azo dye is built by first generating a diazonium salt from a primary aromatic amine and then coupling it with an activated aromatic ring. Nitrobenzene is reduced with Sn/HCl to aniline; aniline is diazotized with

N a N O_{2} / H C l

at low temperature to give benzenediazonium chloride; this diazonium salt then couples with β-naphthol under alkaline (NaOH) conditions at the position ortho to the –OH group, forming the

- N = N -

azo linkage. This reduction–diazotization–coupling sequence is the one that produces the azo dye.

JEE Main · 2025 · 29 Jan 2025 · Shift 2 · Single correct option

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