Question

Arrange the following free radicals in the correct order of their stability:

• A. CH\textsubscript{2} = CH• \quad (ii) CH\textsubscript{3}• \quad (iii) CH\textsubscript{3}–CH–CH\textsubscript{3}• \quad (iv) (CH\textsubscript{3})\textsubscript{3}C• }
• B. i > ii > iii > iv
• C. iv > iii > ii > i
• D. i < ii < iii < iv

Hint:

Remember: More substituted carbon radicals (like tertiary) are more stable due to hyperconjugation and electron-donating alkyl groups.

Answer 1

The Correct Option is B

Free radical stability increases with the number of alkyl substituents due to hyperconjugation and inductive effects. Tertiary radicals like (CH\textsubscript{3})\textsubscript{3}C• are most stable, followed by secondary (CH\textsubscript{3}–CH–CH\textsubscript{3}•), primary (CH\textsubscript{3}•), and least stable are vinylic radicals like CH\textsubscript{2}=CH•.