Q. Aniline in a set of the following reactions yielded a coloured product Y: C₆H₅NH₂ —(NaNO₂/HCl, 273–278 K)→ X —(N,N-dimethylaniline)→ Y The structure of Y would be
A) CH₃NH–C₆H₄–N=N–C₆H₄–NHCH₃ (both para)
B) C₆H₅–N=N–C₆H₄–N(CH₃)₂ (para)
C) CH₃NH–C₆H₄–NH–C₆H₄–NHCH₃ (both para)
D) CH₃–C₆H₄–N=N–C₆H₄–NH₂ (both para)
Explanation
[Solution from source] Aniline with NaNO₂/HCl at 273–278 K gives benzenediazonium chloride (X). This couples with N,N-dimethylaniline at the para position to give the yellow azo dye p-(dimethylamino)azobenzene, C₆H₅–N=N–C₆H₄–N(CH₃)₂. The other structures do not contain the unchanged phenyl ring from aniline joined to the dimethylamino ring. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.