Question

Choose the correct option(s) regarding the stability of free radical formed after breaking of the bonds indicated by the arrows:
​​​​​​​

• A. $\left(a\right)$ is more stable than $\left(b\right)$
• B. $\left(c\right)$ is more stable than $\left(b\right)$
• C. $\left(a\right)$ is the least stable.
• D. $\left(b\right)$ is the most stable.

Answer 1

Answer: (C), (D)

The correct options are
C $\left(a\right)$ is the least stable.
D $\left(b\right)$ is the most stable.

Free radical formed after breaking of bond $\left(a\right)$ :

$1\alpha -\text{Hydrogen}$ is present.

Free radical formed after breaking of bond $\left(b\right)$ :

$7\alpha -\text{Hydrogens}$ are present.

Free radical formed after breaking of bond $\left(c\right)$ :

​​​​​​​$4\alpha -\text{Hydrogen}$ are present.
Since,
Free radical stability $\propto$ Number of $\alpha$-H.
Stability order is :
$\left(b\right)>\left(c\right)>\left(a\right)$