Which of the following reagents is selectively used to perform side-chain bromination on ethylbenzen — Aromatic Hydrocarbons Chemistry Question

💡 Solution & Explanation

To achieve side-chain halogenation, a free radical mechanism is required. N-Bromosuccinimide (NBS) in the presence of light or heat generates a low, steady concentration of bromine radicals. These selectively abstract the weaker benzylic hydrogen to form a highly resonance-stabilized benzylic radical, which then reacts to form 1-bromo-1-phenylethane.