Here are the essential concepts you must grasp in order to answer the question correctly.
Electrophilic Aromatic Substitution
Electrophilic aromatic substitution (EAS) is a fundamental reaction mechanism in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. In the case of benzene, the aromatic system is stabilized by resonance, making it less reactive than alkenes. However, when a strong electrophile, such as bromine in the presence of a catalyst, is introduced, it can lead to the substitution of a hydrogen atom, forming a bromobenzene product.
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Bromination of Aromatic Compounds
Bromination is a specific type of electrophilic aromatic substitution where bromine (Br2) reacts with an aromatic compound. In the presence of a catalyst like iron (Fe) or aluminum chloride (AlCl3), bromine can generate a more reactive bromonium ion, which facilitates the substitution. The reaction typically results in the formation of brominated aromatic products, such as bromobenzene, while releasing hydrogen bromide (HBr) as a byproduct.
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Mechanism of Allylic Bromination.
Radical Mechanism
In the context of the question, the presence of a nail suggests a radical mechanism may be involved, particularly if the nail is made of iron. This can lead to the generation of bromine radicals, which can react with benzene to form bromobenzene. This radical pathway differs from the traditional electrophilic substitution, as it involves the formation of radical intermediates rather than a stable carbocation, influencing the reaction's selectivity and product distribution.
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The mechanism of Radical Polymerization.