Which of the following substituents acts as a deactivating group but still directs the incoming elec — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

Halogens like Chlorine ($-Cl$) are the classical exceptions in directing effects. Because of their high electronegativity, their inductive effect ($-I$) dominates their resonance effect ($+M$) in the ground state, making the ring less reactive than benzene. However, during the transition state, the $+M$ effect stabilizes the ortho and para arenium ions, making them ortho/para directors.