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

Equilibrium Constant

Organic Chemistry

3. Acids and Bases

Equilibrium Constant

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2:14 minutes

Problem 47b

Textbook Question

Calculate the equilibrium constant for each of the acid–base reactions shown.
b.

Verified step by step guidance

Identify the acid and base on both sides of the reaction. Determine which species is donating a proton (acid) and which is accepting a proton (base).

Write the equilibrium constant expression for the acid-base reaction. The equilibrium constant (K_eq) is given by the formula:

K

_eq = K_a^acid1K_a^acid2, where

K

_a values correspond to the acids on each side of the reaction.

Look up the pKa values for the acids on both sides of the reaction. Recall that

K

_a = 10^-pKa, so you can calculate the Ka values if needed.

Substitute the Ka values into the equilibrium constant expression. Ensure that the acid on the reactant side is in the numerator and the acid on the product side is in the denominator.

Simplify the expression to determine the equilibrium constant (K_eq). This will indicate whether the reaction favors the reactants or the products.

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Key Concepts

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

Acid-Base Reactions

Acid-base reactions involve the transfer of protons (H+) between reactants. An acid is a substance that donates protons, while a base accepts them. Understanding the nature of the acids and bases involved is crucial for predicting the direction of the reaction and calculating the equilibrium constant.

Equilibrium Constant (K)

The equilibrium constant (K) quantifies the ratio of the concentrations of products to reactants at equilibrium for a given reaction at a specific temperature. For acid-base reactions, K can be expressed in terms of the concentrations of the conjugate acids and bases. A larger K value indicates a reaction that favors product formation.

Conjugate Acid-Base Pairs

Conjugate acid-base pairs consist of an acid and its corresponding base that differ by a single proton. When an acid donates a proton, it forms its conjugate base, and vice versa. Recognizing these pairs is essential for calculating equilibrium constants and understanding the dynamics of acid-base reactions.

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