Textbook Question
Arrange these compounds in order of increasing boiling points and explain your rationale for the order.
(i) formic acid
(ii) methyl formate
(iii) formamide.
Ch.17 Carboxylic Acids and Their Derivatives
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187
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Table of contents
- Ch.1 Matter and Measurements27
- Ch.2 Atoms and the Periodic Table20
- Ch.3 Ionic Compounds8
- Ch.4 Molecular Compounds23
- Ch.5 Classification & Balancing of Chemical Reactions12
- Ch.6 Chemical Reactions: Mole and Mass Relationships28
- Ch.7 Chemical Reactions: Energy, Rate and Equilibrium64
- Ch.8 Gases, Liquids and Solids24
- Ch.9 Solutions52
- Ch.10 Acids and Bases25
- Ch.11 Nuclear Chemistry22
- Ch.12 Introduction to Organic Chemistry: Alkanes57
- Ch.13 Alkenes, Alkynes, and Aromatic Compounds47
- Ch.14 Some Compounds with Oxygen, Sulfur, or a Halogen50
- Ch.15 Aldehydes and Ketones45
- Ch.16 Amines42
- Ch.17 Carboxylic Acids and Their Derivatives57
- Ch.18 Amino Acids and Proteins82
- Ch.19 Enzymes and Vitamins63
- Ch.20 Carbohydrates44
- Ch.21 The Generation of Biochemical Energy65
- Ch.22 Carbohydrate Metabolism45
- Ch.23 Lipids42
- Ch.24 Lipid Metabolism33
- Ch.25 Protein and Amino Acid Metabolism24
- Ch.26 Nucleic Acids and Protein Synthesis45
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187Not the one you use?Change textbook
Chapter 17, Problem 39b
Suppose you have a sample of benzoic acid dissolved in water.
b. Now assume that aqueous NaOH is added to the benzoic acid solution until pH 12 is reached. Draw the structure of the major organic species present.
Verified step by step guidance1
Identify the chemical structure of benzoic acid. Benzoic acid is an aromatic carboxylic acid with the formula C₆H₅COOH. The carboxylic acid group (-COOH) is the functional group responsible for its acidic properties.
Understand the reaction between benzoic acid and NaOH. Benzoic acid reacts with a strong base like NaOH in a neutralization reaction. The hydroxide ion (OH⁻) from NaOH deprotonates the carboxylic acid group (-COOH), forming water (H₂O) and the conjugate base of benzoic acid, which is the benzoate ion (C₆H₅COO⁻).
Recognize the effect of pH 12. At pH 12, the solution is strongly basic, meaning that essentially all of the benzoic acid will have been converted to its conjugate base, the benzoate ion (C₆H₅COO⁻). This is because the pKa of benzoic acid is approximately 4.2, and at pH 12, the environment is far above the pKa, favoring the deprotonated form.
Draw the structure of the major organic species. The major organic species present at pH 12 is the benzoate ion. Its structure consists of a benzene ring (C₆H₅) attached to a carboxylate group (-COO⁻), where the hydrogen atom from the carboxylic acid group has been removed.
Summarize the reaction and the resulting species. The reaction can be summarized as: C₆H₅COOH + OH⁻ → C₆H₅COO⁻ + H₂O. The major organic species present at pH 12 is the benzoate ion (C₆H₅COO⁻).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Benzoic Acid
Benzoic acid is a simple aromatic carboxylic acid with the formula C6H5COOH. It is characterized by a benzene ring attached to a carboxyl group (-COOH). In aqueous solutions, benzoic acid can partially dissociate to form benzoate ions (C6H5COO-) and hydrogen ions (H+), depending on the pH of the solution.
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pH and Acid-Base Reactions
pH is a measure of the acidity or basicity of a solution, with lower values indicating higher acidity. When NaOH, a strong base, is added to benzoic acid, it reacts to neutralize the acid, forming water and benzoate ions. At pH 12, the solution is highly basic, leading to the complete deprotonation of benzoic acid, resulting in the predominant presence of benzoate ions.
Organic Species in Aqueous Solutions
In aqueous solutions, the major organic species present depend on the pH and the nature of the solute. At pH 12, benzoic acid is fully deprotonated, and the major species is the benzoate ion (C6H5COO-). Understanding the structure of these species is crucial for predicting their behavior in chemical reactions and their interactions in biological systems.
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Related Practice
Textbook Question
Write the equation for the ionization of hexanoic acid in water at pH 7.4.
Textbook Question
Draw the structures of the following compounds and use dashed lines to indicate where they form hydrogen bonds to other molecules of the same kind: (i) formic acid
Textbook Question
Give systematic names for the following carboxylic acids:
d. CH3(CH2)5COOH
Textbook Question
Suppose you have a sample of benzoic acid dissolved in water.
c. Finally, assume that aqueous HCl is added to the solution from (b) until pH 2 is reached. Draw the structure of the major organic species present.
Textbook Question
Give systematic names for the following carboxylic acids:
d.