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**Aryl halides are prepared** by direct halogenation of arenes with which catalyst?
APd/C
BNa metal
CAnhydrous Lewis acid (e.g. FeCl₃, AlCl₃, FeBr₃)
DConcentrated H₂SO₄
Answer & Solution
Correct answer: C. Anhydrous Lewis acid (e.g. FeCl₃, AlCl₃, FeBr₃)
Electrophilic aromatic substitution: Lewis acid (FeX₃, AlCl₃) activates X₂ by polarising it. Generates electrophile X⁺ that attacks the aromatic ring. Direct halogenation with Cl₂/Br₂ works; F₂ is too reactive, I₂ needs oxidant to drive the equilibrium.
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