Question

(81 (ii) The nitrogen atom of pyridine contains a lone pair of electrons, however this lone electron pair is incapable of increasing the electron density of the n electron system to any significant degree. With the aid of diagrams explain why this is the case.

Answer 1

Explanation has been given below

Step-by-step explanation:

• Lone pair on N atom in pyridine lies in
  `sp^(2)` hybridized orbital of N atom.
• Delocalization of this lone pair into requires
  `sp^(3)` hybridized state of N atom.
• 
  `sp^(3)` hybridization of N atom is not possible because it will lead to highly strained 6-membered cyclic structure.
• Hence lone pair on N atom does not involve in delocalization and thereby does not increase electron density in aromatic ring.
• Diagram has been shown below.