Arrange the following free radicals in the order of decreasing stability: methyl `(I)`, vinyl `(II)`, allyl `(III)`, benzyl `(IV)`

Options

A. IgtIIgtIIIgtIV
B. IIIgtIIgtIgtIV
C. IgtIgtIVgtIII
D. IVgtIIIgtIgtII

Answer

D

Explanation

Among the alkyl free radicals, tertiary alkyl free radicals are most stable and methyl free radical is least stable.
Benzyl and allyl free radicals are resonacne stabilized and are more stable than alkyl free radicals. Vinyl radical is least stable as the odd electron is present on `sp^(3)` C-atom.

`underset("Resonacne in allyl radical")(CH_(2)=CH-overset(**)(C)H_(2)larroverset(**)(C)H_(2))-CH=CH_(2)`
`therefore`Order is benzyl `(IV)gtAllyl(III)gt"Methyl"(I)gt"Vinyl"(II)`