91Ó°ÊÓ

The more stable a lone pair electron is, the less basic it will be.

The less stable a lone pair of electrons is, the more basic it will be.

The structures of the two compounds are:

Structure of compound A

Structure of compound B

In compound A, the nitrogen is very close to the aromatic ring. Hence, the lone pair electrons of the nitrogen atom undergo delocalization. Thus, the electron donation capacity of nitrogen atoms will decrease.

Lone pair in delocalization

But the nitrogen atom in compound B is far from the aromatic ring. Hence, the lone pair electrons of nitrogen atoms are readily available for donation to any other electrophile.

Lone pair available for donation to acid

Therefore, compound B is a stronger base than compound A.