3 - Methylhex-2-ene on reaction with HBr in presence of peroxide forms an addition product (A). The number…

The hydrogen bromide addition in peroxides follows Anti Markovnikov rule.  Anti Markovnikov  addition reaction is found to follow a free radical mechanism. The peroxide compound involved helps in the generation of free radicals. The Anti-Markovnikov rule defines regiochemistry in which the substituent is attached to a less substituted carbon instead of the more substituted carbon.

The reaction of $3-$Methylhex-2-ene  with $\mathrm{HBr}$ in presence of peroxide, takes place as follows,

$2$ chiral carbons, here, so, total number of stereoisomers will be $2^{\mathrm{n}}=2^2=4$