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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Problem 63c

Textbook Question

Parts (a)–(d) of this assessment assist in the development of what will become a common theme in organic reactions and should be worked in order. [Think carefully about how each question relates to the others.]
(c) Without worrying about the mechanism of the reaction, estimate an equilibrium constant for the following carbonyl addition reaction based on the relative stability of the Lewis bases.

Verified step by step guidance

Analyze the reaction: The image shows a nucleophilic addition reaction where a methyl anion (CH₃⁻) attacks the carbonyl carbon of acetone (propanone), resulting in the formation of a tetrahedral intermediate with a negatively charged oxygen atom.

Consider the relative stability of the Lewis bases: The methyl anion (CH₃⁻) is a strong nucleophile but less stable due to its negative charge on a carbon atom. The negatively charged oxygen in the product is more stable because oxygen is more electronegative and better accommodates the negative charge.

Relate stability to equilibrium: The equilibrium constant (K_eq) for the reaction depends on the relative stability of the reactants and products. Since the negatively charged oxygen in the product is more stable than the methyl anion in the reactants, the equilibrium will favor the product side.

Estimate the equilibrium constant qualitatively: A reaction that favors the formation of a more stable product typically has a K_eq greater than 1. Thus, the equilibrium constant for this reaction is expected to be greater than 1, indicating that the product is favored.

Conclude the reasoning: The equilibrium constant estimation is based on the principle that reactions tend to favor the side with more stable species. Here, the stability of the negatively charged oxygen in the product drives the equilibrium toward the product side.

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Key Concepts

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

Equilibrium Constant (K)

The equilibrium constant (K) is a numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium for a given reaction. It provides insight into the position of equilibrium, indicating whether products or reactants are favored. A larger K value suggests that products are favored, while a smaller K indicates a preference for reactants.

Lewis Acids and Bases

Lewis acids and bases are defined by their ability to accept or donate electron pairs, respectively. In the context of carbonyl addition reactions, the stability of the Lewis bases involved can significantly influence the reaction's equilibrium. A more stable Lewis base will favor the formation of products, thereby affecting the equilibrium constant.

Carbonyl Addition Reactions

Carbonyl addition reactions involve the nucleophilic attack of a Lewis base on the electrophilic carbon of a carbonyl group (C=O). This type of reaction is fundamental in organic chemistry, leading to the formation of alcohols or other functional groups. Understanding the stability of the reactants and products is crucial for estimating the equilibrium constant in these reactions.

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