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

7. Substitution Reactions

Substitution Comparison

Organic Chemistry

7. Substitution Reactions

Substitution Comparison

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3:17 minutes

Problem 6b

Textbook Question

What is the major product of each of the following reactions?
b.

Verified step by step guidance

Step 1: Analyze the structure of the starting material. The molecule is a cyclohexane ring with a hydroxyl (-OH) group attached to a tertiary carbon. This tertiary carbon is also bonded to two methyl groups.

Step 2: Recognize the reagent used in the reaction. HBr is a strong acid that can protonate the hydroxyl group, converting it into a good leaving group (water). This sets the stage for a substitution reaction.

Step 3: Protonation of the hydroxyl group occurs first. The oxygen in the -OH group will accept a proton (H⁺) from HBr, forming H₂O as a leaving group.

Step 4: After the leaving group departs, a carbocation intermediate is formed. Since the hydroxyl group is attached to a tertiary carbon, the resulting carbocation is tertiary, which is highly stable due to hyperconjugation and inductive effects.

Step 5: The bromide ion (Br⁻) from HBr will act as a nucleophile and attack the carbocation, resulting in the formation of the major product, which is a tertiary alkyl bromide.

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Key Concepts

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

Nucleophilic Substitution

Nucleophilic substitution is a fundamental reaction mechanism in organic chemistry where a nucleophile replaces a leaving group in a molecule. In the case of alcohols reacting with hydrogen halides like HBr, the hydroxyl group (-OH) is converted into a better leaving group, allowing the bromide ion (Br-) to attach to the carbon atom, forming an alkyl bromide.

Carbocation Stability

Carbocation stability is crucial in determining the outcome of reactions involving alcohols and hydrogen halides. The stability of the carbocation intermediate formed during the reaction influences the major product. Tertiary carbocations are more stable than secondary or primary ones, leading to preferential formation of products that arise from more stable carbocations.

Markovnikov's Rule

Markovnikov's Rule states that in the addition of HX (where X is a halogen) to an alkene or an alcohol, the hydrogen atom will attach to the carbon with the greater number of hydrogen atoms already attached. This rule helps predict the major product of the reaction, guiding the formation of the more stable alkyl halide product when cyclohexanol reacts with HBr.

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