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

Acids and Bases

Organic Chemistry

3. Acids and Bases

Acids and Bases

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4:56 minutes

Problem 57

Textbook Question

Draw the products of the following reactions:
a.
b.
c.

Verified step by step guidance

Step 1: Analyze the reaction in part (a). The reactants are CH₃CH₂OCH₃ (an ether) and BH₃ (borane). Borane is an electron-deficient species due to the incomplete octet of boron, making it a Lewis acid. The lone pair of electrons on the oxygen atom in the ether can act as a Lewis base and donate electrons to boron.

Step 2: Predict the product for part (a). The oxygen atom in CH₃CH₂OCH₃ will form a coordinate covalent bond with boron in BH₃. This results in the formation of a Lewis acid-base adduct. The structure of the product will show the oxygen atom bonded to boron, with boron completing its octet.

Step 3: Analyze the reaction in part (b). The reactants are CH₃CH₂NH₂ (an amine) and AlF₃ (aluminum trifluoride). Aluminum in AlF₃ is electron-deficient due to its incomplete octet, making it a Lewis acid. The lone pair of electrons on the nitrogen atom in the amine can act as a Lewis base and donate electrons to aluminum.

Step 4: Predict the product for part (b). The nitrogen atom in CH₃CH₂NH₂ will form a coordinate covalent bond with aluminum in AlF₃. This results in the formation of a Lewis acid-base adduct. The structure of the product will show the nitrogen atom bonded to aluminum, with aluminum completing its octet.

Step 5: For both reactions, ensure that the products are drawn with proper chemical structures, showing the new bonds formed between the Lewis base (oxygen or nitrogen) and the Lewis acid (boron or aluminum). Include any lone pairs and formal charges if applicable.

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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 electron pair acceptors, while Lewis bases are electron pair donors. In the reactions shown, BH3 acts as a Lewis acid, accepting electron pairs from the ether (CH3CH2OCH3), and AlF3 acts as a Lewis acid, interacting with the amine (CH3CH2NH2). Understanding these definitions is crucial for predicting the products of these reactions.

Nucleophilic Attack

Nucleophilic attack occurs when a nucleophile (an electron-rich species) donates an electron pair to an electrophile (an electron-deficient species). In the first reaction, the ether oxygen donates a pair of electrons to BH3, forming a new bond. Recognizing the nucleophile and electrophile in a reaction helps in determining the products formed.

Reaction Mechanisms

Understanding reaction mechanisms involves knowing the step-by-step process by which reactants transform into products. This includes identifying intermediates and transition states. In the provided reactions, recognizing how the Lewis acids interact with the bases and the resulting bond formations is essential for accurately drawing the products.

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Related Practice

Textbook Question

Consider the following reaction: HBr + ^-C≡N ⇌ Br⁻ + HC≡N

a. What is the acid on the left side of the equation?

b. What is the base on the left side of the equation?

Textbook Question

Which of the following are not acids?

CH₃COOH, CO₂ , HNO₂ , HCOOH, CCl₄

Textbook Question

Write the equation that shows how a buffer made by dissolving CH₃COOH and CH₃COO⁻Na⁺ in water prevents the pH of a solution from changing appreciably when

a. a small amount of H⁺ is added to the solution.

b. a small amount of HO⁻ is added to the solution.

Textbook Question

Antacids are compounds that neutralize stomach acid. Write the equations that show how Milk of Magnesia, Alka-Seltzer, and Tums remove excess acid.

a. Milk of Magnesia: Mg(OH)₂

b. Alka-Seltzer: KHCO₃ and NaHCO₃

c. Tums: CaCO₃

Textbook Question

What is the conjugate base of each of the following?

1. NH₃

2. HBr

3. HNO₃