Answer: Nucleophilic substitution at room temperature with dilute NaOH.
- A Electrophilic aromatic substitution occurring readily on the aromatic ring
- B Reaction with dry Mg in ether to form an aryl Grignard reagent
- C Catalytic reduction with H<sub>2</sub> over Pd to give the parent benzene ring
- D Nucleophilic substitution at room temperature with dilute NaOH
Correct answer: D. Nucleophilic substitution at room temperature with dilute NaOH
Explanation: Haloarenes are very resistant to nucleophilic substitution under mild conditions because the C-X bond has partial double-bond character and the pi cloud repels nucleophiles.
SN2 proceeds in a single step with backside attack and inversion of configuration, while SN1 forms a planar carbocation intermediate first, leading to racemisation.
Concept context
Study carbon-halogen compounds: how they are made, how they react via SN1/SN2 and elimination, their stereochemistry, and their environmental impact.