Textbook Question
Given the following Keq values, how much stronger of a base is acetate (CH3CO2-) than chloride (Cl⁻)?
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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 30a
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) 
Verified step by step guidance1
Step 1: Recall the relationship between pKa and the ratio of acid to conjugate base. The Henderson-Hasselbalch equation is given as: , where [HA] is the concentration of the acid and [A⁻] is the concentration of the conjugate base.
Step 2: Rearrange the Henderson-Hasselbalch equation to isolate the ratio of acid to conjugate base: .
Step 3: Identify the pKa value from the problem. The pKa of the acid is given as 20.
Step 4: Determine the pH of the solution. If the pH is not explicitly provided, it must be assumed or calculated based on additional information. For example, if the solution is neutral, the pH is 7.
Step 5: Substitute the pKa and pH values into the rearranged equation to calculate the ratio of acid to conjugate base. This will yield the ratio .
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
pKₐ and Acid-Base Equilibrium
pKₐ is a measure of the strength of an acid in solution, defined as the negative logarithm of the acid dissociation constant (Kₐ). A lower pKₐ value indicates a stronger acid, which dissociates more completely in solution. Understanding pKₐ is essential for calculating the ratio of acid to conjugate base, as it directly influences the equilibrium position of the acid-base reaction.
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04:00
Determining Acid/Base Equilibrium
Henderson-Hasselbalch Equation
The Henderson-Hasselbalch equation relates the pH of a solution to the pKₐ of the acid and the ratio of the concentrations of the conjugate base and the acid. It is expressed as pH = pKₐ + log([A⁻]/[HA]). This equation is crucial for determining the ratio of acid to conjugate base, as it allows for the calculation of this ratio based on the known pH and pKₐ values.
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05:02Breaking down the different terms of the Gibbs Free Energy equation.
Acid-Base Reaction Dynamics
Acid-base reactions involve the transfer of protons (H⁺) between species, leading to the formation of conjugate acids and bases. The dynamics of these reactions are influenced by factors such as concentration, temperature, and the presence of other ions in solution. Understanding these dynamics is important for accurately calculating the acid to conjugate base ratio, as it affects the equilibrium state of the reaction.
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02:49The Lewis definition of acids and bases.
Related Practice
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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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
How do you know that a proton with a low pKa value is acidic (besides 'I just remember')?
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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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