Ques. 1NEET 2016 (Phase 1)
The correct statement regarding the basicity of arylamines is
- arylamines are generally more basic than alkylamines because of aryl group
- arylamines are generally more basic than alkylamines, because the nitrogen atom in arylamines is sp-hybridised
- arylamines are generally less basic than alkylamines because the nitrogen lone-pair electrons are delocalised by interaction with the aromatic ring -electron system
- arylamines are generally more basic than alkylamines because the nitrogen lone-pair electrons are not delocalised by interaction with the aromatic ring -electron system.
Answer
(3) arylamines are generally less basic than alkylamines because the nitrogen lone-pair electrons are delocalised by interaction with the aromatic ring -electron system
Solution
As per NCERT, in aniline the lone pair on nitrogen is in conjugation with the benzene ring (resonance) ⇒ it is delocalised over the ring.
⇒ The lone pair is less available for protonation.
In alkylamines the lone pair is localised and the +I effect of the alkyl group increases electron density on N.
∴ Arylamines are less basic than alkylamines because the nitrogen lone pair is delocalised by interaction with the aromatic -electron system.
Answer: (3)