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

Ranking Acidity

Organic Chemistry

3. Acids and Bases

Ranking Acidity

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2:33 minutes

Problem 45a

Textbook Question

Which anion in each pair would you expect to react more quickly with H⁺?
(a)

Verified step by step guidance

Identify the two anions in the pair and analyze their structures. Consider factors such as resonance stabilization, electronegativity, and the availability of lone pairs for protonation.

Recall that an anion's reactivity with H⁺ (a proton) depends on its basicity. A stronger base will react more quickly with H⁺ because it has a greater tendency to accept a proton.

Examine the resonance effects: If one anion is resonance-stabilized, it will be less basic because the negative charge is delocalized, making it less available to react with H⁺.

Consider the inductive effects: If an anion has electronegative atoms or groups nearby, they can withdraw electron density, reducing the anion's basicity and reactivity with H⁺.

Compare the two anions based on the above factors and determine which one is more basic and thus more likely to react quickly with H⁺.

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Key Concepts

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

Acidity and Basicity

Acidity refers to the ability of a substance to donate protons (H⁺), while basicity is the ability to accept protons. In organic chemistry, the strength of an acid or base can influence the reactivity of anions. A stronger base will typically react more quickly with protons, making it essential to understand the relative strengths of acids and bases when predicting reaction rates.

Nucleophilicity

Nucleophilicity is a measure of how readily a species donates an electron pair to form a bond with a proton or electrophile. Anions, being negatively charged, are often nucleophiles. The more nucleophilic an anion is, the faster it will react with H⁺. Factors such as charge, electronegativity, and steric hindrance affect nucleophilicity.

Reaction Mechanisms

Understanding reaction mechanisms is crucial for predicting how and why certain reactions occur. In the context of anions reacting with H⁺, the mechanism can involve protonation steps that determine the rate of reaction. Familiarity with common mechanisms, such as acid-base reactions and nucleophilic attacks, helps in analyzing which anion will react more quickly.

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Related Practice

Textbook Question

Identify the most stable conjugate base in each pair. Tell which structural features you analyzed and why you weighted them as you did in picking one answer.

(c)

Textbook Question

Identify the most stable conjugate base in each pair. Tell which structural features you analyzed and why you weighted them as you did in picking one answer.

(e)

Textbook Question

Identify the most acidic proton in each pair. Tell which structural features you analyzed and why you weighted them as you did in picking one answer. [Always start by drawing the conjugate base.]

(a)

Textbook Question

Identify the most acidic proton in each pair. Tell which structural features you analyzed and why you weighted them as you did in picking one answer. [Always start by drawing the conjugate base.]

(h)

Textbook Question

Which anion in each pair would you expect to react more quickly with H⁺?

(b)

Textbook Question

If reacted with a strong base, which of the labeled protons would you expect to be removed first?

Textbook Question

Which is the most acidic compound in each pair?

(a)

Textbook Question

Rank the indicated hydrogen in the following compounds from most acidic to least acidic:

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