Textbook Question
Design an acid–base extraction scheme to separate a mixture of the basic amine N,N-dimethylaniline and naphthalene.
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Ch. 4 - Acids and Bases: Electron Flow
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471
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Table of contents
- Ch. 2 - General Chemistry Translated: Finding the Electrons114
- Ch. 3 - Alkanes and Cycloalkanes: Properties and Conformational Analysis109
- Ch. 4 - Acids and Bases: Electron Flow144
- Ch. 5 - Chemical Reaction Analysis: Thermodynamics and Kinetics118
- Ch. 6 - Stereoisomerism: Arrangement of Atoms in Space112
- Ch. 7 - Principles of Green (Organic) Chemistry3
- Ch. 8 - Alkenes I: Properties and Electrophilic Additions158
- Ch. 9 - Alkenes II: Oxidation and Reduction150
- Ch. 10 - Alkynes: Electrophilic Addition and Redox Reactions101
- Ch. 11 - Properties and Synthesis of Alkyl Halides: Radical Reactions108
- Ch. 12 - Substitution and Elimination: Reactions of Haloalkanes172
- Ch. 13 - Alcohols, Ethers and Related Compounds: Substitution and Elimination239
- Ch. 14 - Structural Identification I: Infrared Spectroscopy and Mass Spectrometry54
- Ch. 15 - Structural Identification II: Nuclear Magnetic Resonance Spectroscopy93
- Ch. 16 - Metals in Organic Chemistry48
- Ch. 17 - Carbonyl Addition Reactions: Aldehydes and Ketones45
- Ch. 18 - Nucleophilic Acyl Substitution I: Carboxylic Acids18
- Ch. 19 - Nucleophilic Acyl Substitution II: Carboxylic Acid Derivatives39
- Ch. 20 - Enolates: Carbonyl Addition and Substitution13
- Ch. 21 - Conjugated Systems I: Stability and Addition Reactions56
- Ch. 22 - Conjugated Systems II: Pericyclic Reactions54
- Ch. 23 - Benzene I: Aromatic Stability and Substitution Reactions64
- Ch. 24 - Benzene II: Reactions Influenced by the Aromatic Ring62
- Ch. 25 - Amines: Structure, Reactions, and Synthesis27
- Ch. 26 - Amino Acids, Proteins, and Peptide Synthesis9
- Ch. 27 - Carbohydrates, Nucleic Acids, and Lipids54
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Not the one you use?Change textbook
Chapter 3, Problem 29
Given the following Keq values, how much stronger of a base is acetate (CH3CO2-) than chloride (Cl⁻)?
Verified step by step guidance1
Step 1: Understand the relationship between K_eq and base strength. The equilibrium constant (K_eq) is related to the acid dissociation constant (K_a) of the conjugate acids. A stronger base corresponds to a weaker conjugate acid, which has a smaller K_a value.
Step 2: Identify the conjugate acids of the bases in question. Acetate (CH₃CO⁻₂) is the conjugate base of acetic acid (CH₃COOH), and chloride (Cl⁻) is the conjugate base of hydrochloric acid (HCl).
Step 3: Use the formula K_a = K_eq for the dissociation of the conjugate acid. Compare the K_a values of acetic acid and hydrochloric acid to determine the relative base strength of acetate and chloride.
Step 4: Calculate the ratio of the K_a values. The relative base strength can be determined by comparing the inverse of the K_a values (since base strength is inversely proportional to acid strength). Use the formula: \( \text{Relative base strength} = \frac{K_{a, \text{HCl}}}{K_{a, \text{CH₃COOH}}} \).
Step 5: Interpret the result. The larger the ratio, the stronger acetate is as a base compared to chloride. This ratio quantifies how much stronger acetate is as a base than chloride.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Equilibrium Constant (K_eq)
The equilibrium constant (K_eq) quantifies the ratio of the concentrations of products to reactants at equilibrium for a reversible reaction. A higher K_eq value indicates that the products are favored, suggesting a stronger tendency for the reaction to proceed in that direction. In the context of acids and bases, K_eq can help determine the relative strengths of different bases.
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02:19
The relationship between equilibrium constant and pKa.
Acidity and Basicity
Acidity refers to the tendency of a substance to donate protons (H⁺), while basicity refers to the ability to accept protons. The strength of a base can be inferred from the K_eq of its conjugate acid; a stronger base corresponds to a weaker conjugate acid. Understanding the relationship between acids and bases is crucial for comparing the basicity of acetate and chloride.
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06:21Understanding the difference between basicity and nucleophilicity.
Conjugate Acid-Base Pairs
Conjugate acid-base pairs consist of two species that differ by the presence of a proton. For example, acetate (CH₃CO⁻₂) is the conjugate base of acetic acid (CH₃COOH), while chloride (Cl⁻) is the conjugate base of hydrochloric acid (HCl). The strength of the conjugate acids can be compared using their K_a values, which directly influences the basicity of their corresponding bases.
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Related Practice
Textbook Question
Given the following Keq values, how much stronger of an acid is methanol (CH3OH) than acetylene (HC≡CH)?
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Textbook Question
Hydrogen gas (H2) has a relatively high pKa value. Is it a stable or unstable acid? Do you expect it to participate in acid–base reactions?
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Textbook Question
An unknown acid (HA) has been identified as very strong. What does this tell you about the stability of the conjugate base, A⁻? Is it strong or weak? Is it reactive or unreactive?
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Textbook Question
Given that the indicated pKa values correspond to the acid dissociation reactions shown, calculate the ratio of acid to conjugate base for the reactions shown.
(a)
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Textbook Question
Given that the indicated pKa values correspond to the acid dissociation reactions shown, calculate the ratio of acid to conjugate base for the reactions shown.
(b)
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