Q. When sec-butylcyclohexane reacts with bromine in the presence of sunlight, the major product is :
A) [image:2025J22S2_Q66_opt_a.png]
B) [image:2025J22S2_Q66_opt_b.png]
C) [image:2025J22S2_Q66_opt_c.png]
D) [image:2025J22S2_Q66_opt_d.png]
Explanation
[Solution by Dr. Abubacker] Free-radical bromination is highly selective for the most stable radical, i.e. a tertiary hydrogen. The side-chain carbon bearing the ring, a methyl and an ethyl group is tertiary and its radical is the best stabilised, so Br ends up on that carbon (option 3). (Medium confidence: the ring carbon is also tertiary; this follows the official key.) Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.