13.16. Addition of HBr to propene yields 2-bromopropane, while in the presence of benzoyl peroxide, the same reaction yields 1-bromopropane. Explain and give mechanism.

Addition of HBr to propene is an ionic electrophilic addition reaction in which the electrophile, i.e., H⁺ first adds to give a more stable 2° carbocation. In the 2^nd step, the carbocation is rapidly attacked by the nucleophile Br~ ion to give 2-bromopropane.

In presence of benzoyl peroxide, the reaction is still electrophilic but the electrophile here is a Br free radical which is obtained by the action of benzoyl peroxide on HBr.

In the first step, Br radical adds to propene to generate the more stable 2° free radical. In the second step, the free radical thus obtained rapidly abstracts a hydrogen atom from HBr to give 1-b

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Addition of HBr to propene is an ionic electrophilic addition reaction in which the electrophile, i.e., H⁺ first adds to give a more stable 2° carbocation. In the 2^nd step, the carbocation is rapidly attacked by the nucleophile Br~ ion to give 2-bromopropane.

In presence of benzoyl peroxide, the reaction is still electrophilic but the electrophile here is a Br free radical which is obtained by the action of benzoyl peroxide on HBr.

In the first step, Br radical adds to propene to generate the more stable 2° free radical. In the second step, the free radical thus obtained rapidly abstracts a hydrogen atom from HBr to give 1-bromopropane.

Even though both the reactions are electrophilic addition in nature, they yield different products because of different order of addition of H and Br atoms.

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<p>Addition of HBr to propene is an ionic electrophilic addition reaction in which the electrophile, i.e., H⁺&nbsp;first adds to give a more stable 2° carbocation. In the 2^nd step, the carbocation is rapidly attacked by the nucleophile Br~ ion to give 2-bromopropane.</p><div><div><picture><source srcset="https://images.shiksha.com/mediadata/images/articles/1742368438phpAircpe_480x360.jpeg" media=" (max-width: 500px)"><img src="https://images.shiksha.com/mediadata/images/articles/1742368438phpAircpe.jpeg" alt="" width="509" height="237"></picture></div><div>In presence of benzoyl peroxide, the reaction is still electrophilic but the electrophile here is a Br free radical which is obtained by the action of benzoyl peroxide on HBr.<br><div><div><picture><source srcset="https://images.shiksha.com/mediadata/images/articles/1742368503php0l16rt_480x360.jpeg" media=" (max-width: 500px)"><img src="https://images.shiksha.com/mediadata/images/articles/1742368503php0l16rt.jpeg" alt="" width="528" height="116"></picture></div><div>In the first step, Br radical adds to propene to generate the more stable 2° free radical. In the second step, the free radical thus obtained rapidly abstracts a hydrogen atom from HBr to give 1-bromopropane.</div><div><div><div class="photo-widget-full"><div class="figure"><picture><source srcset="" media="(max-width: 500px)"><img src="https://images.shiksha.com/mediadata/images/1752142943php5WdiwU.jpeg" alt="" width="772" height="247" loading="lazy"></picture></div></div></div><div><p>Even though both the reactions are electrophilic addition in nature, they yield different products because of different order of addition of H and Br atoms.</p></div></div></div></div></div>

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