Which one of the following reaction sequences will give an azo dye?
- [figure]
- [figure]
- [figure]
- [figure]
Answer
(3) [figure]
Solution
Azo dye = diazotisation + coupling with an activated arene (β-naphthol, alkaline medium).
[figure]
(1) gives a sulphonamide and (2) an amide: no - N=N-; (4) toluene is too weakly activated to couple.
Answer: (3)