Solution
Core Logic
This is the classic Peroxide Effect (Kharasch effect) showing Anti-Markovnikov addition of HBr across an alkene. Ph-CH=CH₂ + HBr Peroxide Ph-CH₂-CH₂-Br (1-Bromo-2-phenylethane is the MAJOR product).
Step 1: Analyze Radical Mechanism (A, B, C)
The reaction proceeds via the most stable free radical intermediate (a secondary benzylic radical). Statement A is correct. Peroxide (Benzoyl peroxide) undergoes homolytic cleavage to form benzoyloxy radicals, which lose CO₂ to form phenyl radicals (Ph). Phenyl radical abstracts H from HBr to form a Bromine radical (Br), not a Hydrogen radical (H). Statement B is false. The abstraction of H from HBr by the phenyl radical (Ph) yields Benzene (Ph-H) as a byproduct. Statement C is correct.
Step 2: Product Check (D, E)
1-Bromo-2-phenylethane is the major product, not the minor product. Statement D is false. In the absence of peroxide, standard electrophilic addition occurs via a stable carbocation intermediate (Markovnikov addition). Statement E is correct.
Final Conclusion
Statements A, C, and E are correct.
Pattern Recognition
Peroxides generate Br, never H. The initiating radical pulls H from H-Br since H-Br is weaker than forming C-H bond, leaving Br to attack the alkene.
Chapter Mix
Class 11 Chemistry: Hydrocarbons