Question

Compare the stability of given free radicals

• A. A > B > C
• B. C > B > A
• C. B > C > A
• D. A > C > B

Answer 1

The correct option is B C > B > A

Here all the structures having $1\alpha$ - hydrogen so stability of the free radical cannot be explained by $\alpha$-hydrogen
$\text{Stability of free radical}\propto \text{+ Inductive effect}\propto \frac{1}{\text{- Inductive effect}}$
Here, $N{O}_2$ shows more $-I$ effect than $CN$, so it will destabilise the radical more than $CN$
$C{H}_3$ shows $+I$ effect and it stabilises the free radical.
Hence the correct order of stability of free radical is
$C>B>A$