Chemistry - GOC Question with Solution | TestHub

Three molecules have equal C–C bond lengths.

Aromaticity: Structures with complete cyclic resonance delocalization attain a uniform bond order, making all their C–C bonds identical.

Molecules (i), (ii), and (vii): The cyclopropenyl cation ($2\pi e^{-}$), benzene ($6\pi e^{-}$), and cyclopentadienyl anion ($6\pi e^{-}$) are all planar, aromatic systems.

Resonance Effect: Due to perfect symmetric resonance in these three rings, single and double bonds fully equalize into intermediate partial double bonds.

Other Structures: Molecules like (iv) and (v) have localized/alternating single and double bonds, while (vi) naphthalene has unequal bond orders due to its fused geometry.