Question

The stability order of alkyl free radicals is?

a) tert.˂sec.˂pri.˂CH3 b) tert.˂pri.˂sec.˂CH3

c) tert. ˃ sec. ˃ pri. ˃ CH3 d) sec. ˃ tert. ˃ pri. ˃ CH3​

Answer 1

Explanation:

The correct order of stability of alkyl free radicals is tert. > sec. > pri. > CH₃ , because we know that alkyl free radicals are e⁻ deficient and it requires e⁻ to attain stability.

So,

In 3° alkyl free radicals it get donation from 3 sides so it gains more stability. (+I effect)

CH₃

|

CH₃-C•

|

CH₃

And

In 2° alkyl free radicals it get donation from 2 side so it gains less stability as compared to 3°

CH₃

|

CH₃-C•

|

H

And

In 1° alkyl free radicals it gets donation from only 1 side so it gains less stability as compared to 3° & 2°

CH₃-CH₂•

And

In methyl carbon free radicals it doesn't gain donation from any side so it's least stable.

CH₃•

Therefore,

Option C is correct.