Question

Question: Rank the following radicals in order of increasing stability.

Short answer

Answer

The rank of the given radicals in the increasing order of stability is as follows:

Step-by-step solution

Stability

The stability of the carbon radical is explained by allylic, 3⁰2⁰,and 1⁰ alkyl carbon radicals.A dot on the carbon represents a carbon radical.

Rank of increasing stability

Structure A is stable due to the presence of an allylic carbon radical. Structure B is stable due to the presence of a 3⁰carbon radical, and structure C is stable due to the presence of a 2⁰carbon radical.

The allylic carbon radical is stabilized by resonance

Resonance structure

The3⁰ carbon radical is more stable than 2⁰ carbon radical because it is stabilized through the electronic effects of other groups attached. In this case, hyperconjugation occurs.

That’s why structure B is more stable than structure C.