Propene is more reactive than ethene towards HBr because

Question

Propene is more reactive than ethene towards HBr because (A) propene can more readily undergo a free radical chain reaction (B) propene gives rise to more stable carbocation (C) the double bond in case of propene is unstable (D) the methyl group attached to double bond withdraws electrons and facilitates the attack

Tardigrade Admin · Accepted Answer

Addition of HBr to ethene takes place by electrophilic addition mechanism

ethene C H_{2} = C H_{2} H B r Ethyl bromide C H_{2} C H_{2} B r

Mechanism

\Rightarrow C H_{2} = C H_{2} H^{+} B r^{-} (i) C H_{3} C H_{2} \oplus B r^{-} C H_{3} C H_{2} B r

Addition of HBr to propene takes place by electrophilic addition mechanism in accordance with Markonikov rule, according to which the negative part of the adding molecule gets attached to that carbon atom

C H_{3} - C H = C H_{2} H B r C H_{3} - B r ∣ C H - C H_{3}

Q. Propene is more reactive than ethene towards HBr because

propene can more readily undergo a free radical chain reaction

propene gives rise to more stable carbocation

the double bond in case of propene is unstable

the methyl group attached to double bond withdraws electrons and facilitates the attack

Q. Propene is more reactive than ethene towards $H B r$ because