Textbook Question
Draw the structures of the following compounds. (Includes both new and old names.)
(k) 3-methylhex-4-yn-2-ol
1
views
Ch.10 - Structure and Synthesis of Alcohols
Wade9th EditionOrganic ChemistryISBN: 9780135213728
Not the one you use?Change textbookSelect a different textbook
Table of contents
- Ch.1 - Structure and Bonding107
- Ch. 2 - Acids and Bases; Functional Groups115
- Ch.3 - Structure and Stereochemistry of Alkanes100
- Ch.4 - The Study of Chemical Reactions99
- Ch.5 - Stereochemistry93
- Ch.6 - Alkyl Halides; Nucleophilic Substitution118
- Ch. 7 - Structure and Synthesis of Alkenes; Elimination158
- Ch.8 - Reactions of Alkenes171
- Ch.9 - Alkynes91
- Ch.10 - Structure and Synthesis of Alcohols143
- Ch.11 - Reactions of Alcohols104
- Ch. 12 - Infrared Spectroscopy and Mass Spectrometry22
- Ch. 13 - Nuclear Magnetic Resonance Spectroscopy45
- Ch. 14 - Ethers, Epoxides, and Thioethers72
- Ch. 15 - Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy89
- Ch. 16 - Aromatic Compounds74
- Ch. 17 - Reactions of Aromatic Compounds126
- Ch. 18 - Ketones and Aldehydes193
- Ch. 19 - Amines129
- Ch. 20 - Carboxylic Acids77
- Ch. 21 - Carboxylic Acid Derivatives141
- Ch. 22 - Condensations and Alpha Substitutions of Carbonyl Compounds175
- Ch. 23 - Carbohydrates and Nucleic Acids93
- Ch. 24 - Amino Acids, Peptides, and Proteins54
Chapter 10, Problem 33a,b
Predict which member of each pair has the higher boiling point, and explain the reasons for your predictions.
a. hexan-1-ol or 3,3-dimethylbutan-1-ol
b. hexan-2-one or hexan-2-ol
Verified step by step guidance1
Step 1: Understand the factors affecting boiling points. Boiling points are influenced by intermolecular forces such as hydrogen bonding, dipole-dipole interactions, and London dispersion forces. Molecules with stronger intermolecular forces generally have higher boiling points.
Step 2: Analyze (a) hexan-1-ol vs. 3,3-dimethylbutan-1-ol. Both are alcohols, meaning they can form hydrogen bonds due to the presence of the hydroxyl (-OH) group. However, hexan-1-ol has a straight-chain structure, which allows for stronger London dispersion forces compared to the branched structure of 3,3-dimethylbutan-1-ol. Branching reduces the surface area available for intermolecular interactions, lowering the boiling point.
Step 3: Analyze (b) hexan-2-one vs. hexan-2-ol. Hexan-2-one is a ketone, which can only exhibit dipole-dipole interactions due to the polar carbonyl group. Hexan-2-ol, on the other hand, is an alcohol and can form hydrogen bonds in addition to dipole-dipole interactions. Hydrogen bonding is significantly stronger than dipole-dipole interactions, so hexan-2-ol is expected to have a higher boiling point.
Step 4: Compare molecular weights and structures. Both pairs of compounds have similar molecular weights, so the differences in boiling points are primarily due to the types and strengths of intermolecular forces rather than size.
Step 5: Summarize the predictions. For (a), hexan-1-ol is predicted to have a higher boiling point due to its straight-chain structure and stronger London dispersion forces. For (b), hexan-2-ol is predicted to have a higher boiling point due to the presence of hydrogen bonding, which is stronger than the dipole-dipole interactions in hexan-2-one.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
7mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Hydrogen Bonding
Hydrogen bonding is a strong type of dipole-dipole interaction that occurs when hydrogen is bonded to highly electronegative atoms like oxygen or nitrogen. In alcohols, the presence of an -OH group allows for hydrogen bonding between molecules, significantly increasing their boiling points compared to hydrocarbons of similar molecular weight, which lack such interactions.
Recommended video:
Guided course
00:48
The definition of hydrogenation.
Molecular Structure and Steric Hindrance
Molecular structure refers to the arrangement of atoms within a molecule, which can influence physical properties like boiling point. Steric hindrance occurs when bulky groups around a functional group impede interactions, such as hydrogen bonding. In the case of 3,3-dimethylbutan-1-ol, the presence of two methyl groups near the -OH group reduces the ability to form hydrogen bonds compared to hexan-1-ol, leading to a lower boiling point.
Recommended video:
Guided course
08:41Review of Molecular Orbitals
Functional Groups and Polarity
Functional groups are specific groups of atoms within molecules that determine their chemical properties. The polarity of a molecule, influenced by its functional groups, affects its boiling point; polar molecules, like alcohols, generally have higher boiling points due to stronger intermolecular forces. In comparing hexan-2-one and hexan-2-ol, the alcohol's -OH group introduces polarity and hydrogen bonding, resulting in a higher boiling point than the ketone.
Recommended video:
Guided course
02:36Identifying Functional Groups
Related Practice
Textbook Question
Predict which member of each pair is more acidic, and explain the reasons for your predictions.
b. cyclohexanol or cyclohexanethiol
2
views
Textbook Question
Predict which member of each group is most soluble in water, and explain the reasons for your predictions.
a. butan-1-ol, pentan-1-ol, or propan-2-ol
1
views
Textbook Question
Predict which member of each pair is more acidic, and explain the reasons for your predictions.
a. cyclopentanol or 3-chlorophenol
1
views
Textbook Question
Draw the structures of the following compounds. (Includes both new and old names.)
i. cyclopent-3-ene-1-thiol
j. dimethyl disulfide
1
views
Textbook Question
Draw the structures of the following compounds. (Includes both new and old names.)
(d) 3-cyclopentylhexan-3-ol
(e) meso-2,4-pentanediol
1
views