Textbook Question
What are the products of the following reactions?
a.
b.
c.
d.
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Ch. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid Derivatives
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. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid DerivativesProblem 30a
Bruice 8th EditionCh. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid DerivativesProblem 30aChapter 17, Problem 30a
The pKa of protonated acetone is about –7.5 and the pKa of protonated hydroxylamine is 6.0.
a. In a reaction with hydroxylamine at pH 4.5 (Figure 16.2), what fraction of acetone is present in its acidic, protonated form?
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Verified step by step guidance1
Step 1: Understand the relationship between pKa and pH. The fraction of a compound in its protonated form can be calculated using the Henderson-Hasselbalch equation: \( \text{pH} = \text{pKa} + \log \left( \frac{[\text{A}^-]}{[\text{HA}]} \right) \). Rearrange this equation to solve for the fraction of the protonated form \( [\text{HA}] \).
Step 2: Identify the relevant pKa value for protonated acetone, which is given as \( -7.5 \). The pH of the reaction is specified as \( 4.5 \). Substitute these values into the Henderson-Hasselbalch equation.
Step 3: Calculate the ratio \( \frac{[\text{A}^-]}{[\text{HA}]} \) using the equation \( \log \left( \frac{[\text{A}^-]}{[\text{HA}]} \right) = \text{pH} - \text{pKa} \). This will give the logarithmic ratio of the deprotonated to protonated forms.
Step 4: Convert the logarithmic ratio to a linear ratio by taking the antilog (10 raised to the power of the calculated value). This will yield \( \frac{[\text{A}^-]}{[\text{HA}]} \).
Step 5: Use the ratio \( \frac{[\text{A}^-]}{[\text{HA}]} \) to calculate the fraction of acetone in its protonated form \( [\text{HA}] \) using the formula \( \text{Fraction of HA} = \frac{1}{1 + \frac{[\text{A}^-]}{[\text{HA}]} } \).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acid-Base Equilibrium
Acid-base equilibrium refers to the balance between proton donors (acids) and proton acceptors (bases) in a solution. The pH of a solution indicates its acidity or basicity, influencing the protonation state of compounds. Understanding this concept is crucial for predicting the fraction of a compound in its protonated form at a given pH.
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04:00
Determining Acid/Base Equilibrium
pKa and pH Relationship
The pKa of a compound is the pH at which half of the species are protonated and half are deprotonated. It is a critical value for determining the protonation state of a compound in solution. By comparing the pH of the solution to the pKa of the compound, one can calculate the fraction of the compound that exists in its protonated form using the Henderson-Hasselbalch equation.
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02:15The pH scale vs. the pKa scale.
Henderson-Hasselbalch Equation
The Henderson-Hasselbalch equation is a mathematical formula used to relate the pH of a solution to the pKa of an acid and the ratio of the concentrations of its protonated and deprotonated forms. It is expressed as pH = pKa + log([A-]/[HA]). This equation is essential for calculating the fraction of acetone that is protonated at a specific pH, allowing for a quantitative analysis of the reaction conditions.
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05:02Breaking down the different terms of the Gibbs Free Energy equation.
Related Practice
Textbook Question
Excess ammonia must be used when a primary amine is synthesized by reductive amination. What product will be obtained if the reaction is carried out with excess carbonyl compound?
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Textbook Question
What are the products of the following reactions? (A trace amount of acid is present in each case.)
a. cyclopentanone + ethylamine
b. cyclopentanone + diethylamine
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Textbook Question
Imines can exist as stereoisomers. The isomers are named using the E,Z system of nomenclature (Section 4.2 ). The lone pair has the lowest priority.
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Draw the structure of each of the following compounds:
a. the (E)-hydrazone of benzaldehyde
b. the (Z)-oxime of propiophenone
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Textbook Question
Why is the pKa value of protonated hydroxylamine (6.0) so much lower than the value of a protonated primary amine such as protonated methylamine (10.7)?
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Textbook Question
A ketone can be prepared from the reaction of a nitrile with a Grignard reagent. Describe the intermediate formed in this reaction, and show how it can be converted to a ketone.
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