Textbook Question
Drawing on what you know about the stereochemistry of alkene addition reactions,
b. predict the configuration of the product of the reaction.
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Ch. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis
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. 7 - The Reactions of Alkynes • An Introduction to Multistep SynthesisProblem 10
Bruice 8th EditionCh. 7 - The Reactions of Alkynes • An Introduction to Multistep SynthesisProblem 10Chapter 8, Problem 10
Why does cis-2-butene have a higher boiling point than trans-2-butene?
Verified step by step guidance1
Understand the structural difference between cis-2-butene and trans-2-butene. Cis-2-butene has both methyl groups on the same side of the double bond, while trans-2-butene has the methyl groups on opposite sides of the double bond.
Recognize that the spatial arrangement of the methyl groups in cis-2-butene creates a dipole moment. The molecule is slightly polar because the electron density is unevenly distributed due to the methyl groups being on the same side.
Compare this to trans-2-butene, which is nonpolar. In trans-2-butene, the methyl groups are on opposite sides, canceling out any dipole moment and resulting in a more symmetrical molecule.
Understand that intermolecular forces play a key role in boiling points. Cis-2-butene, being slightly polar, experiences stronger dipole-dipole interactions compared to trans-2-butene, which only experiences weaker London dispersion forces.
Conclude that the stronger intermolecular forces in cis-2-butene require more energy to overcome during boiling, leading to a higher boiling point compared to trans-2-butene.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Cis-Trans Isomerism
Cis-trans isomerism, also known as geometric isomerism, occurs in compounds with restricted rotation around a double bond. In cis isomers, substituents are on the same side of the double bond, while in trans isomers, they are on opposite sides. This spatial arrangement affects the physical properties of the molecules, including boiling points.
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Polarity and Intermolecular Forces
The boiling point of a substance is influenced by its intermolecular forces, which include hydrogen bonding, dipole-dipole interactions, and London dispersion forces. Cis-2-butene is more polar than trans-2-butene due to its molecular geometry, leading to stronger dipole-dipole interactions. This increased polarity results in a higher boiling point for cis-2-butene.
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Boiling Point Trends
Boiling point trends in organic compounds are often determined by molecular weight, structure, and intermolecular forces. Generally, compounds with stronger intermolecular forces have higher boiling points. In the case of cis-2-butene versus trans-2-butene, the stronger dipole-dipole interactions in the cis form contribute to its higher boiling point compared to the trans form.
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Related Practice
Textbook Question
What orbitals are used to form the carbon–carbon s bond between the highlighted carbons?
g.
h.
i.
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Textbook Question
What ketones are formed from the acid-catalyzed hydration of 3-heptyne?
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Textbook Question
Drawing on what you know about the stereochemistry of alkene addition reactions,
a. write the mechanism for the reaction of 2-butyne with one equivalent of Br2.
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Textbook Question
In Table 7.2, what is the smallest alkane, the smallest terminal alkene, and the smallest terminal alkyne that are liquids at room temperature, which is generally taken to be 20 °C to 25 °C?
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Textbook Question
What orbitals are used to form the carbon–carbon s bond between the highlighted carbons?
a.
b.
c.
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