Textbook Question
Write the structures of the following compounds:
a. Butyldiethylammonium bromide
Ch.16 Amines
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 16, Problem 15
Which is the stronger base in each pair?
a. Ammonia or ethylamine
b.Triethylamine or pyridine
Verified step by step guidance1
Step 1: Understand the concept of base strength. A stronger base has a greater ability to accept protons (H⁺). In organic chemistry, the strength of a base is influenced by the availability of the lone pair of electrons on the nitrogen atom and the surrounding molecular structure.
Step 2: Analyze part (a): Ammonia (NH₃) vs. Ethylamine (CH₃CH₂NH₂). Ethylamine is an amine with an ethyl group attached to the nitrogen. The ethyl group is an electron-donating group, which increases the electron density on the nitrogen atom, making it more available to accept a proton. Ammonia lacks such an electron-donating group, so its nitrogen is less nucleophilic.
Step 3: Conclude for part (a): Ethylamine is the stronger base compared to ammonia because the electron-donating ethyl group enhances the basicity of the nitrogen atom.
Step 4: Analyze part (b): Triethylamine ((CH₃CH₂)₃N) vs. Pyridine (C₅H₅N). Triethylamine has three ethyl groups attached to the nitrogen, which significantly increase the electron density on the nitrogen, enhancing its basicity. Pyridine, on the other hand, is an aromatic compound where the lone pair of electrons on the nitrogen is delocalized into the aromatic ring, reducing its availability to accept a proton.
Step 5: Conclude for part (b): Triethylamine is the stronger base compared to pyridine because the lone pair on the nitrogen in triethylamine is more available for protonation, while in pyridine, the lone pair is partially delocalized into the aromatic system.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Basicity
Basicity refers to the ability of a substance to accept protons (H+) or donate electron pairs. In organic chemistry, stronger bases are typically characterized by their ability to stabilize the positive charge that results from protonation. The strength of a base can be influenced by factors such as electronegativity, steric hindrance, and resonance effects.
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Amine Structure
Amines are organic compounds derived from ammonia by replacing one or more hydrogen atoms with alkyl or aryl groups. The structure of an amine affects its basicity; for instance, primary and secondary amines are generally stronger bases than tertiary amines due to steric hindrance that can impede protonation. The presence of electron-donating groups can also enhance basicity.
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Resonance and Electron Delocalization
Resonance involves the delocalization of electrons across multiple atoms, which can stabilize or destabilize a molecule. In the context of basicity, if a base's lone pair of electrons is involved in resonance with other atoms, it may be less available to accept protons, thus reducing its basicity. Understanding resonance structures helps predict the relative strengths of bases in different pairs.
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Related Practice
Textbook Question
Complete the following equations:
a.
Textbook Question
Write an equation for the acid-base equilibrium of:
a.Pyrrolidine and water
Label each species in the equilibrium as either an acid or a base.
Textbook Question
Write the structure of benzylamine hydrochloride in two different ways, and name the hydrochloride as an ammonium salt.
Textbook Question
Complete the following equations:
c.
1
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Textbook Question
a. For the compound above, identify each nitrogen as either a primary, secondary, tertiary, quaternary, or aromatic amine.