Aromatic Compounds Containing Nitrogen - Result Question 8
8. The increasing order of reactivity of the following compounds towards reaction with alkyl halides directly is
(2019 Main, 12 Jan I)
(a) $(A)<(C)<(D)<(B)$
(b) $(B)<(A)<(C)<(D)$
(c) $(B)<(A)<(D)<(C)$
(d) $(A)<(B)<(C)<(D)$
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Answer:
Correct Answer: 8. (b)
Solution:
- The reaction of alkyl halide with amine or amides is a nucleophilic substitution reaction. More nucleophilic nitrogen is more reactive with alkyl halide. Compound $(A)$ is benzamide and lone pair of ’ $N$ ’ of it, is not available in this compound.
In compound $(D)$, lone pair of ’ $N$ ’ are available but in compound $(C)$, the lone pair of ’ $N$ ’ are not readily available due to the presence of electron withdrawing group $(-CN)$ attach to benzene ring.
In compound (B), i.e. pthalimide, ’ $N$ ’ is not nucleophilic due to the presence of two polar groups attached to it that pulls lone pair towards them. Hence, the correct order is:
$$ (B)<(A)<(C)<(D) \text {. } $$
BETA
