Textbook Question
Explain the relative acidities.
CH2═CHCH2OH, CH3CH2CH2OH, HC≡CCH2OH
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Ch. 2 - Acids and Bases: Central to Understanding Organic Chemistry
Bruice8th EditionOrganic ChemistryISBN: 9780135213711
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Table of contents
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 1)31
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 2)65
- Ch. 2 - Acids and Bases: Central to Understanding Organic Chemistry84
- Ch. 3 - An Introduction to Organic Compounds:Nomenclature, Physical Properties, and Structure183
- Ch. 4 - Isomers: The Arrangement of Atoms in Space121
- Ch. 5 - Alkenes: Structure, Nomenclature, and an Introduction to Reactivity • Thermodynamics and Kinetics83
- Ch. 6 - The Reactions of Alkenes • The Stereochemistry of Addition Reactions175
- Ch. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis119
- Ch. 8 - Delocalized Electrons: Their Effect on Stability, pKa, and the Products of a Reaction • Aromaticity and Electronic Effects: An Introduction to the Reactions of Benzene148
- Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides212
- Ch. 10 - Reactions of Alcohols, Ethers, Epoxides, Amines, and Sulfur-Containing Compounds131
- Ch. 11 - Organometallic Compounds60
- Ch. 12 - Radicals90
- Ch. 13 - Mass Spectrometry; Infrared Spectroscopy; UV/Vis Spectroscopy62
- Ch. 14 - NMR Spectroscopy95
- Ch. 15 - Reactions of Carboxylic Acids and Carboxylic Acid Derivatives123
- Ch. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid Derivatives141
- Ch. 17 - Reactions at the Alpha-Carbon101
- Ch. 18 - Reactions of Benzene and Substituted Benzenes144
- Ch. 19 - More About Amines • Reactions of Heterocyclic Compounds49
- Ch. 20 - The Organic Chemistry of Carbohydrates80
- Ch. 21 - Amino Acids, Peptides, and Proteins57
- Ch. 22 - Catalysis in Organic Reactions and in Enzymatic Reactions35
- Ch. 23 - The Organic Chemistry of the Coenzymes—Compounds Derived from Vitamins1
- Ch. 28 - Pericyclic Reactions58
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Bruice 8th EditionCh. 2 - Acids and Bases: Central to Understanding Organic ChemistryProblem 62a
Bruice 8th EditionCh. 2 - Acids and Bases: Central to Understanding Organic ChemistryProblem 62aChapter 3, Problem 62a
Rank the following alcohols from strongest to weakest acid.
CH2═CHCH2OH; CH3CH2CH2OH; HC≡CCH2OH
Verified step by step guidance1
Step 1: Recall that the acidity of alcohols is influenced by the stability of the conjugate base formed after deprotonation. A more stable conjugate base corresponds to a stronger acid.
Step 2: Analyze the conjugate bases of the given alcohols. For CH2═CHCH2OH, the conjugate base is CH2═CHCH2O⁻. The presence of the vinyl group (CH2═CH-) can stabilize the conjugate base through resonance effects.
Step 3: For CH3CH2CH2OH, the conjugate base is CH3CH2CH2O⁻. This is a simple alkoxide ion without any resonance or inductive effects to stabilize it, making it less stable compared to the conjugate base of CH2═CHCH2OH.
Step 4: For HC≡CCH2OH, the conjugate base is HC≡CCH2O⁻. The presence of the alkyne group (HC≡C-) can exert an inductive effect, pulling electron density away from the oxygen atom and stabilizing the conjugate base.
Step 5: Rank the alcohols based on the stability of their conjugate bases: HC≡CCH2OH (strongest acid due to inductive effect) > CH2═CHCH2OH (moderate acid due to resonance stabilization) > CH3CH2CH2OH (weakest acid due to lack of stabilization).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acidity of Alcohols
The acidity of alcohols is determined by the stability of their conjugate bases after deprotonation. Alcohols can donate a proton (H+) to form an alkoxide ion, and the more stable the alkoxide, the stronger the acid. Factors influencing acidity include the electronegativity of the atoms attached to the hydroxyl group and the overall molecular structure.
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02:02
Forming alcohols through Acid-Catalyzed Hydration.
Inductive Effect
The inductive effect refers to the electron-withdrawing or electron-donating effects of substituents on a molecule. In alcohols, electron-withdrawing groups can stabilize the negative charge on the conjugate base, enhancing acidity. For example, alkyl groups are electron-donating, which can decrease acidity, while groups like halogens can increase it.
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01:47Understanding the Inductive Effect.
Hybridization and Acidity
The hybridization of the carbon atom bonded to the hydroxyl group affects the acidity of alcohols. sp-hybridized carbons (like in HC≡CCH2OH) are more electronegative than sp2 or sp3 hybridized carbons, leading to a more stable conjugate base. Thus, alcohols with sp-hybridized carbons tend to be stronger acids compared to those with sp2 or sp3 hybridization.
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10:43Using bond sites to predict hybridization
Related Practice
Textbook Question
A single bond between two carbons with different hybridizations has a small dipole. What is the direction of the dipole in the indicated bonds?
a.
b.
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Textbook Question
Give the products of the following acid–base reactions and indicate whether reactants or products are favored at equilibrium.
b. CH3CH2OH + -NH2 ⇌
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Textbook Question
For each of the following compounds, draw the form that predominates at pH = 3, pH = 6, pH = 10, and pH = 14:
c. CF3CH2OH (pKa = 12.4)
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Textbook Question
For each compound, indicate the atom that is most apt to be protonated.
a.
b.
c.
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Textbook Question
Give the products of the following acid–base reactions and indicate whether reactants or products are favored at equilibrium.
a.
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