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

6. Thermodynamics and Kinetics

Carbocation Stability

Organic Chemistry

6. Thermodynamics and Kinetics

Carbocation Stability

Previous problemNext problem

5:29 minutes

Problem 26a

Textbook Question

Which carbocation is more stable?
a.

Verified step by step guidance

Step 1: Analyze the stability of carbocations based on their structure. Carbocation stability is influenced by factors such as hyperconjugation, resonance, and inductive effects. Generally, tertiary carbocations are more stable than secondary, which are more stable than primary carbocations.

Step 2: Examine option A. The carbocation is allylic, meaning it is adjacent to a double bond. Allylic carbocations benefit from resonance stabilization, as the positive charge can delocalize over the π-system of the double bond.

Step 3: Examine option B. The carbocation is adjacent to a triple bond. However, sp hybridized carbons are less effective at stabilizing positive charges due to their high electronegativity, making this carbocation less stable.

Step 4: Examine option C. Similar to option B, the carbocation is adjacent to a triple bond. The same reasoning applies: sp hybridized carbons do not stabilize positive charges well, so this carbocation is also less stable.

Step 5: Examine option D. The carbocation is allylic and benefits from resonance stabilization, similar to option A. However, the additional hydrogen on the central carbon in D does not significantly affect the resonance stabilization compared to A. Both A and D are likely to be more stable than B and C.

Verified video answer for a similar problem:

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

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Carbocation Stability

Carbocation stability is influenced by the degree of substitution at the positively charged carbon atom. Tertiary carbocations (three alkyl groups attached) are more stable than secondary (two alkyl groups) and primary (one alkyl group) due to hyperconjugation and inductive effects, which help to disperse the positive charge.

Hyperconjugation

Hyperconjugation is a stabilizing interaction that occurs when the electrons in a sigma bond (C-H or C-C) interact with an adjacent empty p-orbital of a carbocation. This interaction allows for the delocalization of the positive charge, enhancing the stability of the carbocation, particularly in more substituted carbocations.

Inductive Effect

The inductive effect refers to the electron-withdrawing or electron-donating effects of substituents through sigma bonds. Alkyl groups are electron-donating, which can help stabilize a carbocation by reducing the positive charge through the inductive effect, making carbocations with more alkyl groups more stable.

Watch next

Master Determining Carbocation Stability with a bite sized video explanation from Johnny

Start learning

Which carbocation is more stable? a.

Key Concepts

Carbocation Stability

Hyperconjugation

Inductive Effect

Watch next

Which carbocation is more stable?
a.