Correct order of basic strength of Pyrrole, Pyridine and Piperidine is : [figure]
- Pyridine > Piperidine > Pyrrole
- Pyrrole > Piperidine > Pyridine
- Pyrrole > Pyridine > Piperidine
- Piperidine > Pyridine > Pyrrole
Answer
(4) Piperidine > Pyridine > Pyrrole
Solution
Basic strength depends on how available the lone pair on N is.
Piperidine: sp3 N with a localised lone pair, so it is the strongest base.
Pyridine: sp2 N (more s-character holds the lone pair closer), but the lone pair is localised (not in the π sextet), so it is weaker.
Pyrrole: the lone pair is part of the aromatic sextet (delocalised) and is hardly available, so it is the weakest.
∴ Piperidine > Pyridine > Pyrrole
Answer: (4)