During the electrophilic aromatic substitution of benzene, an intermediate known as the Wheland inte — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

The arenium ion (sigma complex) is a true intermediate, lying in an energy valley. The attack of the electrophile causes one carbon to become $sp^3$ hybridized, breaking the cyclic conjugation. The remaining $4\pi$ electrons are delocalized via resonance over the other 5 $sp^2$ hybridized carbon atoms.