Question

Explain in detail how is furan is aromatic?

Answer 1

Well, a molecule is aromatic if it has `(4n+2)*pi` electrons constrained in a planar ring with `pi` electron conjugation all the way around...

Explanation:

And we look at `"furan"`, `C_4H_4O`....

There are FOUR `"carbon-based"` `pi-"electrons"`...AND ONE of the TWO oxygen-based lone pairs are conceived to participate in the heterocycle….and thus with SIX electrons delocalized this fulfils the electron-count criterion for aromaticity...and hence furan, and pyrrole, `C_4H_4NH`, and thiophene, `C_4H_4S`...are all aromatic systems with peculiar and parallel reactivity with respect to aromatic benzene...