Given below are two statements:
Statement I: Aniline is less basic than acetamide.
Statement II: In aniline, the lone pair of electrons on nitrogen atom is delocalised over benzene ring due to resonance and hence less available to a proton.
Choose the most appropriate option:
Statement I: Aniline is less basic than acetamide.
Statement II: In aniline, the lone pair of electrons on nitrogen atom is delocalised over benzene ring due to resonance and hence less available to a proton.
Choose the most appropriate option:
- (A)Statement I is true but statement II is false.
- (B)Statement I is false but Statement II is true✓ Correct
- (C)Both Statement I and Statement II are true.
- (D)Both Statement I and Statement II are false.
Answer: (B)
Solution
In acetamide the nitrogen lone pair is delocalised into the carbonyl group, and a carbonyl group withdraws electron density far more effectively than a benzene ring; protonating that nitrogen would also destroy the amide resonance altogether. The lone pair of aniline is delocalised only into the ring, and aniline is accordingly a far stronger base than acetamide, which makes Statement I wrong.
Statement II describes that delocalisation correctly: the nitrogen lone pair of aniline enters the ring system, is less available to a proton, and the anilinium ion loses this stabilisation on protonation, which is why aniline is a weaker base than an aliphatic amine.
Statement I is false but Statement II is true.
Statement II describes that delocalisation correctly: the nitrogen lone pair of aniline enters the ring system, is less available to a proton, and the anilinium ion loses this stabilisation on protonation, which is why aniline is a weaker base than an aliphatic amine.
Statement I is false but Statement II is true.
JEE Main · 2021 · 27 Jul 2021 · Shift 1 · Single correct option