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.]
(d)
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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 52h
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) 
Verified step by step guidance1
Start by drawing the conjugate base for each molecule in the pair. To do this, remove one proton (H⁺) from each molecule and represent the resulting structure. This step is crucial because the stability of the conjugate base determines the acidity of the proton.
Analyze the stability of the conjugate base formed. Look for structural features such as resonance stabilization, inductive effects, and hybridization of the atom bearing the negative charge. Resonance stabilization is particularly important because it delocalizes the negative charge, making the conjugate base more stable.
Consider the electronegativity of the atom that bears the negative charge in the conjugate base. A more electronegative atom can better stabilize the negative charge, increasing the acidity of the proton attached to it.
Evaluate the inductive effects caused by nearby electronegative atoms or groups. Electronegative substituents can pull electron density away from the negatively charged atom in the conjugate base, stabilizing it further and increasing the acidity of the proton.
Compare the conjugate bases of the two molecules in the pair based on the above factors (resonance, electronegativity, inductive effects, and hybridization). The proton whose removal leads to the more stable conjugate base is the most acidic proton in the pair.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acidity and pKa
Acidity in organic chemistry refers to the tendency of a compound to donate a proton (H+). The strength of an acid is often measured by its pKa value; lower pKa values indicate stronger acids. Understanding the relationship between acidity and pKa is crucial for identifying the most acidic proton in a given pair, as it allows for comparison of the stability of the conjugate bases formed after deprotonation.
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Identifying pKa values
Conjugate Base Stability
The stability of a conjugate base significantly influences the acidity of the corresponding acid. Factors such as electronegativity, resonance, and inductive effects can stabilize the negative charge on the conjugate base. When analyzing pairs of acids, one must consider how these structural features affect the stability of the conjugate bases, as a more stable conjugate base corresponds to a stronger acid.
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Resonance and Inductive Effects
Resonance involves the delocalization of electrons across multiple atoms, which can stabilize a conjugate base by spreading out the negative charge. Inductive effects refer to the influence of electronegative atoms or groups that can withdraw electron density, further stabilizing the conjugate base. Both resonance and inductive effects are critical in determining which proton is more acidic, as they directly impact the stability of the resulting conjugate base.
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01:47Understanding the Inductive Effect.
Related Practice
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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.]
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Textbook Question
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