By Team Aakash Byju's
If you know the resonance structures of Furan, Pyrrol and Thiphene you would notice that furan contains oxygen, pyrrol contains nitrogen and Thiophene contains sulphur.
So, the reactivity of these organic compounds is as shown below.
This is because the availability of electrons at the ring carbon defines its reactivity.
Pyrrole has electron-rich carbons due to the presence of trivalent nitrogen in it, which is more reactive or less stable.
Furan is less reactive then pyrrol because the electronegativity.
The sulphur in the thiophene has a lower electronegativity compared to furan or pyrrole. It withdraws fewer electrons from carbon than furan.
Hence, the thiophene is more stable than furan and pyrrole. So, the stability order is