Textbook Question
For each of the following, give the systematic name and the common name (if it has one) and then indicate whether it is a primary, secondary, or tertiary amine:
d.
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Ch. 3 - An Introduction to Organic Compounds:Nomenclature, Physical Properties, and Structure
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. 3 - An Introduction to Organic Compounds:Nomenclature, Physical Properties, and StructureProblem 31d
Bruice 8th EditionCh. 3 - An Introduction to Organic Compounds:Nomenclature, Physical Properties, and StructureProblem 31dChapter 4, Problem 31d
Predict the approximate size of the following bond angles.
(d) the C—N—C bond angle in a quaternary ammonium salt
Verified step by step guidance1
Review the structure of a quaternary ammonium salt. A quaternary ammonium salt has a central nitrogen atom bonded to four alkyl or aryl groups and carries a positive charge. The nitrogen is sp³ hybridized, meaning it forms four sigma bonds.
Recall the ideal bond angles for sp³ hybridized atoms. In an sp³ hybridized geometry, the electron pairs are arranged in a tetrahedral shape to minimize electron pair repulsion. The ideal bond angle for a tetrahedral geometry is approximately 109.5°.
Consider the effect of the positive charge on the nitrogen atom. The positive charge does not significantly alter the geometry because all four substituents are bonded to the nitrogen atom, and there are no lone pairs to cause additional repulsion.
Compare this situation to other sp³ hybridized atoms. Since there are no lone pairs on the nitrogen atom in a quaternary ammonium salt, the bond angles are expected to be close to the ideal tetrahedral angle of 109.5°.
Conclude that the C—N—C bond angle in a quaternary ammonium salt is approximately 109.5°, as the geometry is determined by the sp³ hybridization and the absence of lone pairs on the nitrogen atom.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Hybridization
Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals that can accommodate bonding. In the case of quaternary ammonium salts, the nitrogen atom typically undergoes sp³ hybridization, leading to the formation of four equivalent sp³ hybrid orbitals that arrange themselves in a tetrahedral geometry.
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Using bond sites to predict hybridization
Bond Angles
Bond angles are the angles formed between two bonds that share a common atom. In a tetrahedral arrangement, such as that found in quaternary ammonium salts, the ideal bond angle is approximately 109.5 degrees. However, the presence of different substituents can slightly alter these angles.
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Steric Effects
Steric effects refer to the influence of the spatial arrangement of atoms on the reactivity and stability of a molecule. In quaternary ammonium salts, the bulky alkyl groups attached to the nitrogen can create steric hindrance, which may affect the bond angles slightly, but the overall tetrahedral geometry remains dominant.
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Related Practice
Textbook Question
Predict the approximate size of the following bond angles.
(b) the C—N—C bond angle in a secondary amine
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Textbook Question
Which of the preceding compounds forms hydrogen bonds with a solvent such as ethanol?
4. CH3CH2CH2NHCH3
5. CH3CH2CH2COOH
6. CH3CH2CH2CH2F
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Textbook Question
Which of the following compounds forms hydrogen bonds between its molecules?
1. CH3CH2OCH2CH2OH
2. CH3CH2N(CH3)2
3. CH3CH2CH2CH2Br
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Textbook Question
What is the smallest straight-chain alkane that is a liquid at room temperature (which is about 25 °C)?
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Textbook Question
Predict the approximate size of the following bond angles.
(a) the C—O—C bond angle in an ether
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