Assertion (A) Propene on addition with hydrogen bromide in the presence of peroxide gives 1-bromopropane as…
Assertion (A) Propene on addition with hydrogen bromide in the presence of peroxide gives 1-bromopropane as the major product.
Reason (R) l-bromopropane is the major product because it is formed through the stable carbocation.
The correct answer is
(A) and (R) are correct, (R) is the correct explanation of (A)
(A) and (R) are correct but (R) is not the correct explanation of (A)
(A) is correct but (R) is not correct
(A) is not correct but (R) is correct
Solution
Addition of $\mathrm{HBr}$ to propene is an example of an electrophilic addition reaction. The electrophile attacks the double bond to form $1^{\circ}$ and $2^{\circ}$ carbocations, and since $2^{\circ}$ carbocation is more stable the major product of the reaction is 2-bromopropane. The reaction follows Markownikoff's rule, but in the presence of per-oxide if follows anti-Markownikoff's rule and gives 1-bromopropane.