Chemistry - GOC Question with Solution | TestHub

Aromatic compounds must be cyclic, planar, fully conjugated and contain (4n + 2) π electrons.

Checking all 9 structures:

(2) Benzene ring present → aromatic (6π e⁻).

(3) Benzene → aromatic (6π e⁻).

(4) Cyclopentadienyl cation → 4π e⁻, antiaromatic → not aromatic.

(5) Cycloheptatrienyl anion → 8π e⁻ → not aromatic.

(6) Polycyclic aromatic system → aromatic.

(8) Borole-type ring has 6π e⁻ delocalization → aromatic.

(9) Oxonium-containing ring has 6π e⁻ conjugation → aromatic.

Hence aromatic compounds are (1), (2), (3), (6), (8) and (9).