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.
(a)
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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 51e
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) 
Verified step by step guidance1
Analyze the conjugate bases in the given pair by identifying the acidic hydrogen that would be removed to form each conjugate base. Use the Bronsted-Lowry definition of acids and bases, where the conjugate base is formed by the loss of a proton (H⁺).
Examine the stability of each conjugate base by considering resonance effects. If the negative charge on the conjugate base can be delocalized through resonance, it will increase the stability of that base. Write out the resonance structures, if applicable, to visualize this delocalization.
Evaluate the inductive effects in each conjugate base. Electronegative atoms or groups near the negatively charged atom can stabilize the charge by withdrawing electron density through sigma bonds. Compare the extent of inductive stabilization in each structure.
Assess the hybridization of the atom bearing the negative charge in each conjugate base. A negative charge on an sp-hybridized atom is more stable than on an sp² or sp³ atom due to the increased s-character, which holds the charge closer to the nucleus.
Compare the overall stability of the conjugate bases based on the factors above (resonance, inductive effects, and hybridization). The conjugate base with the most stabilizing features will be the most stable. Clearly state which structural features were most influential in your decision and why.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Conjugate Bases
A conjugate base is the species that remains after an acid donates a proton (H+). The stability of a conjugate base is crucial in determining the strength of its corresponding acid; stronger acids have more stable conjugate bases. Factors influencing stability include electronegativity, resonance, and the size of the atom bearing the negative charge.
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Conjugated states
Resonance Stabilization
Resonance stabilization occurs when a negative charge can be delocalized over multiple atoms through resonance structures. This delocalization lowers the energy of the conjugate base, making it more stable. When comparing conjugate bases, those that can participate in resonance are generally more stable than those that cannot.
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Electronegativity and Charge Distribution
Electronegativity refers to the ability of an atom to attract electrons. In the context of conjugate bases, a more electronegative atom stabilizes a negative charge better than a less electronegative one. When analyzing conjugate bases, the distribution of charge relative to electronegativity helps determine which base is more stable, as negative charges are more stable on electronegative atoms.
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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.
(f)
925
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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.]
(b)
828
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Textbook Question
If reacted with a strong base, which of the labeled protons would you expect to be removed first?
909
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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)
1160
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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)
1410
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