In anthracene, electrophilic attack occurs preferentially at which of the following positions to max — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

In anthracene, electrophilic attack at the central C-9 or C-10 positions yields an arenium ion intermediate whose canonical forms leave two fully intact, isolated benzene rings on either side. Attack at any outer ring position (C-1 or C-2) leaves only a single fused naphthalene ring system. Because the resonance energy of two isolated benzene rings ($2 \times 36$ kcal/mol) is significantly higher than that of one naphthalene ring ($\approx 61$ kcal/mol), attack at the C-9/C-10 positions is strongly preferred.