Textbook Question
Given the Keq values for the following acid–base reactions, identify the strongest acid and the strongest base.
(c)
2
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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 23b
Given the Keq values for the following acid–base reactions, identify the strongest acid and the strongest base.
(b) 
Verified step by step guidance1
Step 1: Analyze the equilibrium constant (K_eq) provided in the reaction. A very large K_eq value, such as 1.0 × 10^20, indicates that the reaction strongly favors the products. This suggests that the conjugate acid and conjugate base on the product side are weaker than the acid and base on the reactant side.
Step 2: Identify the acids and bases in the reaction. On the reactant side, methanamine (CH3NH2) acts as the acid, and methanide (CH3⁻) acts as the base. On the product side, methane (CH4) is the conjugate acid, and methylamide (CH3NH⁻) is the conjugate base.
Step 3: Compare the strength of the acids. Methane (CH4) is the conjugate acid of methanide (CH3⁻), and methanamine (CH3NH2) is the acid on the reactant side. Since the equilibrium strongly favors the formation of methane, methane is the weaker acid, making methanamine the stronger acid.
Step 4: Compare the strength of the bases. Methylamide (CH3NH⁻) is the conjugate base of methanamine (CH3NH2), and methanide (CH3⁻) is the base on the reactant side. Since the equilibrium strongly favors the formation of methylamide, methylamide is the weaker base, making methanide the stronger base.
Step 5: Conclude that the strongest acid in the reaction is methanamine (CH3NH2), and the strongest base is methanide (CH3⁻).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acid-Base Equilibrium
Acid-base equilibrium refers to the state in which the rates of the forward and reverse reactions of an acid-base reaction are equal, resulting in constant concentrations of reactants and products. The equilibrium constant (K_eq) quantifies this balance, with larger values indicating a stronger tendency for the reaction to favor products, thus identifying stronger acids and bases.
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Determining Acid/Base Equilibrium
Strength of Acids and Bases
The strength of an acid or base is determined by its ability to donate protons (H+) or accept protons, respectively. Stronger acids have higher K_eq values, indicating they dissociate more completely in solution, while stronger bases have a greater tendency to accept protons. In the context of the given reaction, comparing K_eq values helps identify the strongest acid and base.
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Conjugate Acid-Base Pairs
Conjugate acid-base pairs consist of an acid and its corresponding base that differ by a single proton. In the reaction provided, methanide and methanamine are conjugate pairs with their respective products, methylamide and methane. Understanding these pairs is crucial for determining the relative strengths of acids and bases based on their K_eq values.
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Related Practice
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?
Textbook Question
Given the Keq values for the following acid–base reactions, identify the strongest acid and the strongest base.
(a)
1
views
Textbook Question
Given the value of Keq for the following acid–base reactions, identify the weakest acid and the weakest base.
(c)
2
views
Textbook Question
An unknown base (B⁻) has been identified as very weak. What does this tell you about the strength of its conjugate acid, HB? Is it stable or unstable? Is it reactive or unreactive?
Textbook Question
Given the value of Keq for the following acid–base reactions, identify the weakest acid and the weakest base.
(b)
2
views