MDCAT Aromatic Chemistry & Benzene 2026

Benzene Structure

• C₆H₆; sp² carbons; all bond lengths equal (1.39 Å)
• Delocalised π electrons form a ring above and below the plane
• Aromaticity (Hückel): cyclic + planar + 4n+2 π electrons

Electrophilic Aromatic Substitution

• Halogenation (Cl₂/FeCl₃)
• Nitration (HNO₃/H₂SO₄)
• Sulphonation (conc. H₂SO₄)
• Friedel-Crafts alkylation / acylation (AlCl₃)

Substitution preserves aromaticity; addition would destroy it.