Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

10. Addition Reactions

Hydrohalogenation

Organic Chemistry

10. Addition Reactions

Hydrohalogenation

Previous problemNext problem

Problem 61g(iii)

Textbook Question

Predict the product(s) that would result when the alkenes shown here are allowed to react under the following conditions: (iii) HBr, H₂O₂
(g)

Verified step by step guidance

Step 1: Recognize the reaction conditions. The presence of HBr and H₂O₂ indicates that this is a free radical addition reaction, which follows anti-Markovnikov regioselectivity. This is due to the peroxide effect (also known as the Kharasch effect).

Step 2: Understand the mechanism. In the presence of H₂O₂, the reaction proceeds via a radical mechanism rather than the typical electrophilic addition. The bromine atom will add to the less substituted carbon of the double bond, contrary to Markovnikov's rule.

Step 3: Identify the alkene structure. Examine the given alkene and determine the positions of the double bond and substituents. This will help you predict where the bromine atom will attach.

Step 4: Predict the product. Based on anti-Markovnikov addition, the bromine atom will attach to the less substituted carbon of the double bond, while the hydrogen atom will attach to the more substituted carbon.

Step 5: Verify stereochemistry (if applicable). If the alkene is asymmetric or has stereochemical implications, consider whether the product will be a racemic mixture or have specific stereochemistry due to the radical mechanism.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Electrophilic Addition

Electrophilic addition is a fundamental reaction mechanism in organic chemistry where an electrophile reacts with a nucleophile, typically involving alkenes. In the case of alkenes reacting with HBr, the double bond acts as a nucleophile, attacking the electrophilic hydrogen atom, leading to the formation of a carbocation intermediate. This process is crucial for predicting the products of reactions involving alkenes.

Markovnikov's Rule

Markovnikov's Rule states that in the addition of HX (where X is a halogen) to an alkene, the hydrogen atom will attach to the carbon with the greater number of hydrogen atoms already attached. This rule helps predict the regioselectivity of the reaction, guiding the formation of the more stable carbocation and ultimately influencing the major product formed during the reaction with HBr.

Anti-Markovnikov Addition

Anti-Markovnikov addition occurs when the addition of HX to an alkene results in the halogen attaching to the less substituted carbon atom. This is often facilitated by the presence of peroxides (like H₂O₂) in the reaction, which can lead to a radical mechanism. Understanding this concept is essential for predicting the products when alkenes react with HBr in the presence of H₂O₂, as it alters the expected regioselectivity.

Watch next

Master General properties of hydrohalogenation. with a bite sized video explanation from Johnny

Start learning