COMEDK202510 May 2025Morning ShiftChemistryGeneral Organic ChemistryActual
Arrange the following free radicals in the increasing order of their stability:
Options
- AA < B < D < C
- BC < D < B < A
- CA < B < C < D
- DC < B < D < A
Correct answer
C. A < B < C < D
Step-by-step solution
The stability of free radicals is primarily determined by resonance, hyperconjugation, and the inductive effect. Structure A is an isopropyl radical, which is a secondary ( 2^ ) alkyl radical. It is stabilized by hyperconjugation from 6 -hydrogens. Structure B is a tert-butyl radical, which is a tertiary ( 3^ ) alkyl radical. It is stabilized by hyperconjugation from 9 -hydrogens. Thus, B is more stable than A. Structure C is an allyl radical ( CH₂=CH-CH₂^ ), which is stabilized by resonance. The unpaired electron