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

Reaction Mechanism

Organic Chemistry

3. Acids and Bases

Reaction Mechanism

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3:48 minutes

Problem 52a,b

Textbook Question

Each of these compounds can react as an electrophile. In each case, use curved arrows to show how the electrophile would react with the strong nucleophile sodium ethoxide, Na⁺ ⁻OCH₂CH₃.
a.
b. NH₄⁺

Verified step by step guidance

Identify the electrophilic center in each compound. For compound (a), the carbonyl carbon is electrophilic due to the polarization of the C=O bond. For compound (b), the nitrogen atom in NH4+ is electrophilic due to its positive charge.

Consider the nucleophile, sodium ethoxide (Na+ −OCH2CH3). The ethoxide ion (−OCH2CH3) is a strong nucleophile due to the presence of a negatively charged oxygen atom.

For compound (a), draw a curved arrow from the lone pair on the oxygen atom of the ethoxide ion to the electrophilic carbonyl carbon. This represents the nucleophilic attack on the carbonyl carbon.

For compound (b), draw a curved arrow from the lone pair on the oxygen atom of the ethoxide ion to the nitrogen atom in NH4+. This represents the nucleophilic attack on the positively charged nitrogen.

After the nucleophilic attack, consider the possible rearrangements or changes in bonding. For compound (a), the carbonyl oxygen may become negatively charged, and for compound (b), the nitrogen may lose a proton, resulting in NH3.

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Key Concepts

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

Electrophiles

Electrophiles are species that accept electron pairs from nucleophiles during chemical reactions. They are typically positively charged or have a partial positive charge, making them attractive to electron-rich species. In the context of organic reactions, understanding the nature of electrophiles is crucial for predicting reaction pathways and mechanisms.

Nucleophiles

Nucleophiles are electron-rich species that donate an electron pair to electrophiles in a chemical reaction. They can be negatively charged ions or neutral molecules with lone pairs of electrons. Recognizing the strength and reactivity of nucleophiles, such as sodium ethoxide in this case, is essential for understanding how they interact with electrophiles.

Curved Arrows in Mechanisms

Curved arrows are used in organic chemistry to illustrate the movement of electron pairs during chemical reactions. The tail of the arrow indicates the source of the electrons, while the head points to the destination. Mastery of using curved arrows is vital for accurately depicting reaction mechanisms and understanding how reactants transform into products.

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Related Practice

Textbook Question

Each of these compounds can react as an electrophile. In each case, use curved arrows to show how the electrophile would react with the strong nucleophile sodium ethoxide, Na⁺ ⁻OCH₂CH₃.

(d) BH₃

Textbook Question

In each reaction, label the reactants as Lewis acids (electrophiles) or Lewis bases (nucleophiles). Use curved arrows to show the movement of electron pairs in the reactions. Draw any nonbonding electrons to show how they participate in the reactions.

(b)

Textbook Question

(a)

Textbook Question

Each of these compounds can react as a nucleophile. In each case, use curved arrows to show how the nucleophile would react with the strong electrophile BF₃.

(a)

(b)

Textbook Question

Label the reactants in these acid–base reactions as Lewis acids (electrophiles) or Lewis bases (nucleophiles). Use curved arrows to show the movement of electron pairs in the reactions.

(d)

Textbook Question

Label the reactants in these acid–base reactions as Lewis acids (electrophiles) or Lewis bases (nucleophiles). Use curved arrows to show the movement of electron pairs in the reactions.

(b)

Textbook Question

Label the reactants in these acid–base reactions as Lewis acids (electrophiles) or Lewis bases (nucleophiles). Use curved arrows to show the movement of electron pairs in the reactions.

(a)

Textbook Question

Identify the arrow types that are shown in each of these arrow-pushing mechanisms.

(iv)

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