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

16. Conjugated Systems

Stability of Conjugated Intermediates

Organic Chemistry

16. Conjugated Systems

Stability of Conjugated Intermediates

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Problem 7

Textbook Question

Look closely at the resonance structures of the benzylic anions, radicals, and cations in Figures 24.2–24.4. On which benzene carbons did the charge/radical exist in the resonance structures—that is, were they ortho, meta, or para?

Verified step by step guidance

Begin by understanding the concept of resonance structures. Resonance structures are different Lewis structures for the same molecule that show the delocalization of electrons. They are used to represent molecules where the electron distribution cannot be described by a single Lewis structure.

Identify the benzylic position in the benzene ring. The benzylic position refers to the carbon atom directly attached to the benzene ring, which can bear a charge or radical.

Examine the resonance structures of benzylic anions, radicals, and cations. In these structures, the charge or radical can be delocalized across the benzene ring, affecting different carbon atoms.

Determine the positions of the benzene carbons where the charge or radical is delocalized. These positions can be ortho (adjacent to the benzylic position), meta (one carbon away from the benzylic position), or para (opposite to the benzylic position).

Analyze the resonance structures to see which positions (ortho, meta, or para) are involved in the delocalization of the charge or radical. This will help you understand the stability and reactivity of the benzylic intermediates.

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Key Concepts

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

Resonance Structures

Resonance structures are different ways of drawing the same molecule that illustrate the delocalization of electrons. In organic chemistry, they help visualize how electrons can be distributed across a molecule, particularly in systems with conjugated double bonds or lone pairs. The actual structure of the molecule is a hybrid of these resonance forms, which contributes to its stability and reactivity.

Benzylic Position

The benzylic position refers to the carbon atom directly attached to a benzene ring. This position is significant because it can stabilize charges or radicals through resonance with the aromatic system. Understanding the reactivity and stability of benzylic anions, radicals, and cations is crucial for predicting the behavior of these species in chemical reactions.

Ortho, Meta, and Para Positions

Ortho, meta, and para refer to the relative positions of substituents on a benzene ring. Ortho indicates adjacent carbons, meta indicates carbons separated by one carbon, and para indicates carbons opposite each other on the ring. The stability and reactivity of intermediates like anions, radicals, and cations can vary significantly depending on their position relative to other substituents, influencing the overall reaction pathway.

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