NEET 2023, Chemistry Q9: Valence Bond Theory And Hybridisation

Pyridine (${\text{C}}_5{\text{H}}_5\text{N}$) has a six-membered aromatic ring with five CH carbons and one ring nitrogen.

$\sigma$ bonds: five C–H + five C–C(or C–N) ring bonds + one ring C–N $=6$ ring $\sigma$ + $5$ C–H = $11$.

$\pi$ bonds: three within the aromatic ring.

Lone pair: one on the nitrogen, in the $s{p}^2$ orbital pointing out of the ring (not part of the aromatic $\pi$ system).

Hence $11$ $\sigma$, $3$ $\pi$, $1$ lone pair.