---
title: "Addition of HBr to an alkene Template | MolDraw"
url: https://www.moldraw.com/templates/hbr-addition/
description: "Addition of HBr to an alkene template: Propene and HBr: the π bond takes H⁺ to form the secondary cation, which bromide captures to give 2-bromopropane.…"
lang: en
publisher: Scidart Academy
generated: 2026-10-28
---
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# Addition of HBr to an alkene template

![Addition of HBr to an alkene template: Propene and HBr: the π bond takes H⁺ to form the secondary cation, which bromide captures to give 2-bromopropane.](https://www.moldraw.com/templates/hbr-addition.webp)

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Propene and HBr: the π bond takes H⁺ to form the secondary cation, which bromide captures to give 2-bromopropane.

## Mechanism step by step

Markovnikov’s rule: H goes to the carbon that already has more H, through the more stable cation

1. **Protonation** – The π bond attacks H: secondary cation
2. **Bromide capture** – Br⁻ adds to the cation

## Key points

- Markovnikov: the more substituted (more stable) carbocation forms.
- Rearrangements can follow if a hydride or methyl shift gives a better cation.
- With peroxides HBr adds the other way round, by a radical chain.
- HCl and HI add the same way; HI fastest.

Drawn with 25 atoms, 6 arrows, 4 shapes – every one editable in MolDraw.

## Sources

- [Clayden, Greeves & Warren, Organic Chemistry, 2nd ed., OUP 2012, ch. 19](https://openlibrary.org/isbn/9780199270293) Textbook
- [Smith, March's Advanced Organic Chemistry, 8th ed., Wiley 2020](https://openlibrary.org/isbn/9781119371809) Textbook

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