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

13. Alcohols and Carbonyl Compounds

Nucleophilic Addition

Organic Chemistry

13. Alcohols and Carbonyl Compounds

Nucleophilic Addition

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6:15 minutes

Problem 67b

Textbook Question

Within each set of structures, indicate which will react fastest, and which slowest, toward nucleophilic addition in basic conditions.
(b)

Verified step by step guidance

Step 1: Analyze the chemical structures provided. The four compounds are benzaldehyde derivatives with varying substituents attached to the carbonyl group. These substituents will influence the reactivity toward nucleophilic addition under basic conditions.

Step 2: Recall the concept of electrophilicity. The carbonyl carbon in aldehydes and ketones is electrophilic due to the polarization of the C=O bond. Substituents that increase electron density on the carbonyl carbon decrease its electrophilicity, while substituents that withdraw electron density increase electrophilicity.

Step 3: Compare the substituents attached to the carbonyl group in each structure. The first structure has a methyl group, the second structure has a hydrogen atom (aldehyde), the third structure has an ethyl group, and the fourth structure has a propyl group. Larger alkyl groups donate electron density via hyperconjugation and inductive effects, reducing electrophilicity.

Step 4: Rank the reactivity based on substituent effects. Aldehydes (second structure) are generally more reactive than ketones (first, third, and fourth structures) because the hydrogen atom does not donate electron density. Among the ketones, the one with the smallest alkyl group (first structure) will react faster than those with larger alkyl groups (third and fourth structures).

Step 5: Conclude the ranking. The second structure (aldehyde) will react fastest due to its high electrophilicity, while the fourth structure (ketone with a propyl group) will react slowest due to the electron-donating effects of the larger alkyl group.

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Key Concepts

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

Nucleophilic Addition

Nucleophilic addition is a fundamental reaction in organic chemistry where a nucleophile attacks an electrophilic carbon atom, typically in carbonyl compounds. This reaction is crucial for understanding how different functional groups interact with nucleophiles, influencing the rate of reaction based on steric and electronic factors.

Basic Conditions

Basic conditions refer to an environment where the pH is greater than 7, often involving the presence of hydroxide ions (OH-). In nucleophilic addition reactions, basic conditions can enhance the nucleophilicity of certain species, affecting the reactivity of the substrates involved, particularly carbonyl compounds.

Steric and Electronic Effects

Steric effects relate to the spatial arrangement of atoms in a molecule, which can hinder or facilitate the approach of a nucleophile. Electronic effects involve the distribution of electron density, influencing the electrophilicity of the carbon atom. Both effects are critical in determining the relative rates of nucleophilic addition reactions among different structures.

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Within each set of structures, indicate which will react fastest, and which slowest, toward nucleophilic addition in basic conditions.(b)

Key Concepts

Nucleophilic Addition

Basic Conditions

Steric and Electronic Effects

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Within each set of structures, indicate which will react fastest, and which slowest, toward nucleophilic addition in basic conditions.
(b)