Question

• A. Piperidine>Pyridine>Pyrrole
• B. Pyrrole>Pyridine>Piperidine
• C. Pyridine>Piperidine>Pyrrole
• D. Pyrrole>Piperidine >Pyridine

Answer 1

The Correct Option is A

The basicity order of Piperidine, Pyridine, and Pyrrole is determined by their structures and electron distribution.

1. Piperidine: A saturated six-membered heterocyclic amine. Its nitrogen atom's lone pair is readily available for protonation, classifying it as a strong base.
2. Pyridine: Features a nitrogen atom within an aromatic six-membered ring. The nitrogen's lone pair, not part of the aromatic sextet, is available for bonding, though resonance stabilization slightly reduces its availability compared to Piperidine.
3. Pyrrole: Contains nitrogen in a five-membered aromatic ring. The nitrogen's lone pair is delocalized within the aromatic system, significantly limiting its availability for protonation. Consequently, Pyrrole is less basic than both Piperidine and Pyridine.

The order of basic strength, based on lone pair availability for protonation, is:

• Piperidine > Pyridine > Pyrrole

This sequence reflects the decreasing availability of the lone pair, from highest in Piperidine to lowest in Pyrrole, as previously detailed.