Question

Write a resonance form for pyrrole in which nitrogen has a formal charge of 1. Are comparable resonance forms possible for pyridine

Answer 1

Answer:

See explanation and image attached

Explanation:

Here attached are resonance forms of pyrrole and pyridine. The images were obtained from quora and researchgate respectively.

Now, we can see that in the resonance forms of pyrrole, the nitrogen atom in the heterocycle has a formal charge of +1. However, in the six membered pyridine hetrocycle, the nitrogen atom may have a formal charge of -1 or +1 as shown in the canonical structures attached. The structures in which nitrogen has a +1 formal charge in pyridine are comparable to structures obtained from pyrrole. These structures have less contribution to the structure of pyridine.