Question

In pyrrole,

The electron density is maximum on:

• A. $2\text{and}3$
• B. $3\text{and}4$
• C. $2\text{and}4$
• D. $2\text{and}5$

Answer 1

The correct option is D $2\text{and}5$

The electrons current of the pyrrole is delocalized in the ring. The electron density of nitrogen in a pyrole ring is in resonance with the pi electrons of the ring. It is written in the form of following structures:


All the five structures are termed as the resonating structures of pyrrole. Each of the structures contributes equally to the resonance energy of the molecule. The resonating structure indicate that the nitrogen carries positive charge and the four carbon atoms carries negative charge.
Of the five resonating structure the change separation is less in structure $III$ and $IV$. However, the charge separation is more in $II$ and $V$. This result in more stability to the structure $III$ and $IV$ where the negative charge is present at the $C-2$ and $C-5$ carbon atoms.