Question

Which radical is responsible for the observed selectivity in the chain reaction below?

• A. $C{l}^{\ast }$
• B. $B{r}^{\ast }$
• C. $H^{\ast }$
• D. $2^{\circ }$ radical

Answer 1

The correct option is B $B{r}^{\ast }$

$B{r}^{\ast }$ radical is highly selective, produces more stable $2^{\circ }$ free radical selectively.

Mainly two types of carbon-free radical possible, first at primary carbon outside the ring (less stable) and $2^{\circ }$ carbon free radical which is part of ring.

$2^{\circ }$ is more stable than $1^{\circ }$, so major product contains almost 98%.