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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1:18 minutes

Problem 50i

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.
i.

Verified step by step guidance

Identify the Lewis acid and Lewis base: In the given reaction, BF₃ is a Lewis acid because it can accept an electron pair, and CH₂=CH₂ is a Lewis base because it can donate an electron pair.

Recognize the electrophile and nucleophile: The Lewis acid (BF₃) acts as an electrophile, and the Lewis base (CH₂=CH₂) acts as a nucleophile.

Draw the curved arrow: Use a curved arrow to indicate the movement of electron pairs from the π bond of the alkene (CH₂=CH₂) to the electron-deficient carbon atom bonded to BF₃.

Understand the reaction mechanism: The electron pair from the alkene attacks the carbocation, forming a new bond between the alkene and the carbocation, resulting in the extended carbon chain.

Label the final structure: After the electron pair movement, the BF₃ group is attached to the extended carbon chain, and the positive charge is now on the terminal carbon atom of the chain.

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Key Concepts

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

Lewis Acids and Bases

Lewis acids are species that accept electron pairs, while Lewis bases donate electron pairs. In the given reaction, BF3 acts as a Lewis acid because it can accept electron pairs, and the alkene (CH2=CH2) acts as a Lewis base, donating electron pairs to form a bond with the carbocation.

Electrophiles and Nucleophiles

Electrophiles are electron-deficient species that seek electrons, while nucleophiles are electron-rich species that donate electrons. In the reaction, the carbocation (CH2+) is an electrophile, seeking electrons from the nucleophilic alkene (CH2=CH2), which donates electrons to form a new bond.

Curved Arrow Notation

Curved arrows are used in organic chemistry to depict the movement of electron pairs during reactions. In the image, curved arrows should show the electron pair from the alkene moving towards the carbocation, indicating the formation of a new bond and the electron flow from the nucleophile to the electrophile.

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Related Practice

Textbook Question

For the following acid–base pairs, (v) show a mechanism for the reaction;

(e)

Textbook Question

Identify the electrophile and the nucleophile in each of the following reaction steps and then draw curved arrows to illustrate the bond-making and bondbreaking processes.

Textbook Question

Identify the electrophile and the nucleophile in each of the following reaction steps and then draw curved arrows to illustrate the bond-making and bondbreaking processes.

Textbook Question

Identify the electrophile and the nucleophile in each of the following reaction steps and then draw curved arrows to illustrate the bond-making and bondbreaking processes.

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.

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.

(e) CH₃CH₂OH

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.

(f) (CH₃)₂S

Textbook Question

Which atoms in the enol ether would you expect to react with Br⁺ ?

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