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

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1:44 minutes

Problem 24

Textbook Question

What is the major product obtained from the addition of HBr to the following compound?

Verified step by step guidance

Step 1: Identify the functional group in the compound. The compound contains a benzene ring attached to a propene group (CH2=CH-CH2). The double bond in the propene group is the site of reactivity for the addition of HBr.

Step 2: Recall the mechanism of electrophilic addition of HBr to alkenes. The reaction proceeds via the formation of a carbocation intermediate. The H+ from HBr adds to one of the carbons in the double bond, leaving the other carbon with a positive charge.

Step 3: Apply Markovnikov's rule to determine the major product. According to Markovnikov's rule, the H+ will add to the carbon in the double bond that has more hydrogen atoms, resulting in the formation of the more stable carbocation. In this case, the H+ will add to the terminal carbon (CH2), forming a secondary carbocation at the middle carbon (CH).

Step 4: Consider the stability of the carbocation. The secondary carbocation formed is stabilized by hyperconjugation and the inductive effect from the benzene ring. This makes the secondary carbocation more stable than a primary carbocation.

Step 5: Complete the reaction by adding the Br- ion to the carbocation. The Br- will attack the positively charged carbon, resulting in the formation of the major product, which is 1-bromo-2-phenylpropane.

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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 or alkynes. In this process, the double or triple bond is broken, allowing new atoms or groups to be added to the molecule. Understanding this mechanism is crucial for predicting the products of reactions involving unsaturated compounds.

Markovnikov's Rule

Markovnikov's Rule states that when HX (where X is a halogen) adds 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 addition reaction, guiding chemists in determining the major product formed during the reaction with HBr.

Carbocation Stability

Carbocation stability is a key concept in organic chemistry that refers to the relative stability of positively charged carbon species. Carbocations are stabilized by alkyl groups through hyperconjugation and inductive effects, with tertiary carbocations being the most stable. Understanding carbocation stability is essential for predicting the pathway and products of electrophilic addition reactions.

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