Textbook Question
For each of the following compounds (here shown in their acidic forms), write the form that predominates in a solution with a pH = 5.5:
c. H3O+ (pKa = −1.7)
d. HBr (pKa = −9)
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 38a,b,c
Bruice 8th EditionCh. 2 - Acids and Bases: Central to Understanding Organic ChemistryProblem 38a,b,cChapter 3, Problem 38a,b,c
Using the table of pKa values given in [Appendix I], answer the following:
a. Which is the most acidic organic compound in the table?
b. Which is the least acidic organic compound in the table?
c. Which is the most acidic carboxylic acid in the table?
Verified step by step guidance1
Step 1: To determine the most acidic organic compound, locate the compound with the lowest pKa value in the table. The lower the pKa value, the stronger the acid. Analyze the table and identify the compound with the smallest pKa value.
Step 2: To find the least acidic organic compound, locate the compound with the highest pKa value in the table. The higher the pKa value, the weaker the acid. Examine the table and identify the compound with the largest pKa value.
Step 3: To identify the most acidic carboxylic acid, focus specifically on compounds containing the carboxylic acid functional group (-COOH). Compare the pKa values of all carboxylic acids listed in the table and select the one with the lowest pKa value.
Step 4: Review the chemical structures provided in the table to ensure the correct identification of functional groups and verify that the selected compounds match the criteria for each part of the question.
Step 5: Summarize the findings for parts a, b, and c based on the analysis of the pKa values and functional groups in the table.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
pKa and Acidity
pKa is a quantitative measure of the strength of an acid in solution. It is the negative logarithm of the acid dissociation constant (Ka), where lower pKa values indicate stronger acids. Understanding pKa values allows chemists to compare the acidity of different compounds, as a compound with a lower pKa will more readily donate a proton (H+) than one with a higher pKa.
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07:45
Identifying pKa values
Carboxylic Acids
Carboxylic acids are organic compounds characterized by the presence of a carboxyl group (-COOH). They are known for their acidic properties due to the ability of the carboxyl group to donate a proton. In the context of the question, identifying the most acidic carboxylic acid involves comparing the pKa values of various carboxylic acids listed in the provided table.
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04:20Carboxylic Acids Nomenclature
Comparative Analysis of Acidity
To determine the most and least acidic compounds from a list, one must perform a comparative analysis of their pKa values. This involves identifying the lowest pKa for the most acidic compound and the highest pKa for the least acidic compound. This analysis is crucial for answering the specific parts of the question regarding the acidity of various organic compounds and carboxylic acids.
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02:41Comparing hydrocarbon acidity
Related Practice
Textbook Question
For each of the following compounds (here shown in their acidic forms), write the form that predominates in a solution with a pH = 5.5:
a. CH3COOH(pKa = 4.76)
b. CH3CH2N+H3 (pKa = 11.0)
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Textbook Question
Fosamax (shown on the previous page) has six acidic groups. The active form of the drug, which has lost two of its acidic protons, is shown in the box.
(Notice that the phosphorus atom in Fosamax and the sulfur atom in [Problem 36] can be surrounded by more than eight electrons because P and S are below the second row of the periodic table.)
a. Why are the OH groups bonded to phosphorus the strongest acids of the six groups?
b. Which of the remaining four groups is the weakest acid?
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Textbook Question
Using the table of pKa values given in [Appendix I] , answer the following:
d. Which is more electronegative: an sp3 oxygen or an sp2 oxygen?
e. Which compounds demonstrate that the relative electronegativities of a hybridized nitrogen atom are sp > sp2 > sp3?
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Textbook Question
For each of the following compounds, indicate the atom that is protonated when an acid is added to a solution of the compound.
a.
b.
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Textbook Question
For each of the following compounds, indicate the atom that is protonated when an acid is added to a solution of the compound.
c.
d.