CBSE Class 12 · 2011 · Delhi · Compounds Containing NitrogenShort Answer

a) Explain why an alkylamine is more basic than ammonia.
b) How would you convert:
i) aniline to nitrobenzene
ii) aniline to iodobenzene?

Answer: (a) +I of R enriches N and stabilises RNH₃⁺. (b)(i) Diazotise → HBF₄ salt → NaNO₂/Cu, Δ. (ii) Diazotise → KI.

Solution

(a) The alkyl group's +I effect makes the lone pair more available and spreads the ammonium charge — RNH

_{2}

> NH

_{3}

.
(b)(i)

C_{6} H_{5} N H_{2} NaN O_{2} /HCl C_{6} H_{5} N_{2}^{+} C l^{-} HB F_{4} C_{6} H_{5} N_{2}^{+} B F_{4}^{-} NaN O_{2} /Cu, Δ C_{6} H_{5} N O_{2}

(ii)

C_{6} H_{5} N_{2}^{+} C l^{-} + KI \to C_{6} H_{5} I + N_{2} + KCl

CBSE Class 12 Board · 2011 · Delhi · Subjective