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

3. Acids and Bases

Equilibrium Constant

Organic Chemistry

3. Acids and Bases

Equilibrium Constant

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4:10 minutes

Problem 17c

Textbook Question

Estimate the K_eq for the following reactions based on the stability of the anions involved.
(c)

Verified step by step guidance

Analyze the reaction: The left side of the equilibrium involves a cyclopropyl anion, while the right side involves a linear alkyl anion. The reaction is a ring-opening process where the cyclopropyl anion is converted into a linear alkyl anion.

Consider the stability of the anions: Cyclopropyl anions are destabilized due to angle strain in the three-membered ring. The linear alkyl anion on the right side is more stable because it lacks ring strain and allows for better delocalization of charge.

Evaluate the electronic effects: The linear alkyl anion benefits from hyperconjugation and inductive effects, which help stabilize the negative charge. Cyclopropyl anions do not have these stabilizing effects to the same extent.

Relate stability to equilibrium constant (K_eq): Since the linear alkyl anion is more stable, the equilibrium will favor the formation of the products (right side of the reaction). A higher stability of the products corresponds to a larger K_eq value.

Conclude the reasoning: The equilibrium constant (K_eq) for this reaction is expected to be greater than 1, as the reaction favors the formation of the more stable linear alkyl anion over the cyclopropyl anion.

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Key Concepts

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

Equilibrium Constant (K_eq)

The equilibrium constant (K_eq) quantifies the ratio of the concentrations of products to reactants at equilibrium for a given reaction. It is a crucial parameter in understanding the extent of a reaction and is influenced by the stability of the species involved. A higher K_eq indicates a greater tendency for the reaction to favor products, while a lower K_eq suggests a preference for reactants.

Stability of Anions

The stability of anions is a key factor in determining the favorability of a reaction. Anions that are more stable (due to factors like resonance, electronegativity, and size) will contribute to a higher K_eq for the reaction. Understanding how different structural features affect anion stability helps predict the direction of equilibrium and the relative concentrations of reactants and products.

Acid-Base Reactions

Acid-base reactions involve the transfer of protons (H+) between species, leading to the formation of anions and cations. The strength of acids and bases can be assessed through their conjugate pairs, where a stronger acid has a weaker conjugate base. This relationship is essential for estimating K_eq, as the stability of the resulting anions directly impacts the equilibrium position of the reaction.

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Related Practice

Textbook Question

Given that the indicated pK_a values correspond to the acid dissociation reactions shown, calculate the ratio of acid to conjugate base for the reactions shown.

(b)

Textbook Question

Hydrogen gas (H₂) has a relatively high pK_a value. Is it a stable or unstable acid? Do you expect it to participate in acid–base reactions?

Textbook Question

For the following acid–base reaction, (b) calculate the equilibrium constant.

Textbook Question

For each of the following acid–base reactions, (ii) calculate K_eq. If a pK_a is not one of the ten common ones we learned in Chapter 4, it will be given to you.

(a)

Textbook Question

Estimate the K_eq for the following reactions based on the stability of the anions involved.

(b)

Textbook Question

Using pKₐ values, calculate K_eq for the following acid–base reaction.

Textbook Question

Using pKₐ values, calculate the equilibrium constants for the following acid–base reactions.

(b)

Textbook Question

Calculate K_eq for the following acid–base reactions.

(b)