Step 1: Understanding the Concept:
Organic reactions follow specific pathways (mechanisms) depending on the reagents, catalysts, and substrates involved. Electrophiles, nucleophiles, and free radicals are common intermediates.
Step 2: Key Formula or Approach:
Identify the attacking species and the nature of the reaction (addition, substitution, etc.) for each organic process.
Step 3: Detailed Explanation:
(A) Williamson Synthesis: Reaction of alkoxide (\( RO^- \)) with alkyl halide to form ether. This is a classic \( S_N2 \) mechanism. (III. Nucleophilic substitution)
(B) Friedel Craft Reaction: Alkylation or acylation of aromatic rings using \( AlCl_3 \) as a catalyst to generate electrophiles. (IV. Electrophilic substitution)
(C) Bromination of vinyl benzene: \( Br_2 \) adds across the double bond of the vinyl group. Alkenes typically undergo this. (I. Electrophilic addition)
(D) Chlorination of toluene in light: Light (\( h\nu \)) initiates radical formation of halogen atoms which substitute at the benzylic position. (II. Free radical substitution)
Matching: A-III, B-IV, C-I, D-II.
Step 4: Final Answer:
Option (B) is the correct match.
