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

21. Aldehydes and Ketones: Nucleophilic Addition

Imine vs Enamine

Organic Chemistry

21. Aldehydes and Ketones: Nucleophilic Addition

Imine vs Enamine

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3:19 minutes

Problem 40c

Textbook Question

Can the rate of hydrate formation be increased by hydroxide ion as well as by acid? Explain.

Verified step by step guidance

Understand the context: Hydrate formation typically involves the addition of water to a carbonyl compound (e.g., aldehyde or ketone) to form a geminal diol. The reaction can be catalyzed by acids or bases, which affect the reaction mechanism differently.

Analyze the role of hydroxide ion: Hydroxide ion (OH⁻) acts as a base and can increase the rate of hydrate formation by nucleophilic attack. The hydroxide ion attacks the electrophilic carbonyl carbon, forming a tetrahedral intermediate.

Compare with acid catalysis: In acid-catalyzed hydrate formation, a proton (H⁺) increases the electrophilicity of the carbonyl carbon by protonating the oxygen atom of the carbonyl group. This makes the carbonyl carbon more susceptible to nucleophilic attack by water.

Explain the mechanism for hydroxide ion catalysis: In the base-catalyzed mechanism, the hydroxide ion directly attacks the carbonyl carbon, forming a negatively charged intermediate. This intermediate then reacts with water to form the hydrate (geminal diol).

Conclude: Yes, the rate of hydrate formation can be increased by hydroxide ion as well as by acid, but the mechanisms differ. Acid catalysis increases the electrophilicity of the carbonyl carbon, while base catalysis provides a strong nucleophile (OH⁻) to initiate the reaction.

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Key Concepts

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

Hydrate Formation

Hydrate formation refers to the process where water molecules bond with a solute, often resulting in a solid compound. This process is crucial in various chemical reactions, particularly in organic chemistry, where the presence of water can significantly influence the reaction pathway and product stability.

Role of Hydroxide Ions

Hydroxide ions (OH-) can act as nucleophiles in chemical reactions, facilitating the formation of hydrates by attacking electrophilic centers in the solute. Their basic nature can also help stabilize transition states, potentially increasing the rate of hydrate formation by promoting the reaction through a different mechanism.

Acid Catalysis

Acid catalysis involves the use of protons (H+) to enhance the rate of a chemical reaction. In the context of hydrate formation, acids can protonate certain functional groups, making them more reactive and thus accelerating the formation of hydrates. This dual role of acids in both stabilizing intermediates and increasing reactivity is essential for understanding reaction kinetics.

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Propose a mechanism for each of the following reactions:

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Predict the products formed when cyclohexanecarbaldehyde reacts with the following reagents.

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Textbook Question

LOOKING AHEAD CHAPTERS 8, 17 In Chapters 8 and 17 we learn two reaction for the synthesis of the alcohol shown. (a) Show a mechanism for each of the reactions. (b) If you were designing a synthetic route, which would be considered more sustainable? Consider all factors. [Assume the starting organic molecules are equally green.]

Textbook Question

Rank the following compounds from largest K_eq to smallest K_eq for hydrate formation:

Textbook Question

Which of the following are a. hemiacetals? b. acetals? c. hydrates?

Textbook Question

Rank the following carbonyl compounds in order of increasing equilibrium constant for hydration:

CH₃COCH₂Cl ClCH₂CHO CH₂O CH₃COCH₃ CH₃CHO