Textbook Question
A carboxylic acid ( pKa = 5) is 1011 times more acidic than an alcohol (pKa = 16). Why?
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Ch. 24 - Benzene II: Reactions Influenced by the Aromatic Ring
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471
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Table of contents
- Ch. 2 - General Chemistry Translated: Finding the Electrons114
- Ch. 3 - Alkanes and Cycloalkanes: Properties and Conformational Analysis109
- Ch. 4 - Acids and Bases: Electron Flow144
- Ch. 5 - Chemical Reaction Analysis: Thermodynamics and Kinetics118
- Ch. 6 - Stereoisomerism: Arrangement of Atoms in Space112
- Ch. 7 - Principles of Green (Organic) Chemistry3
- Ch. 8 - Alkenes I: Properties and Electrophilic Additions158
- Ch. 9 - Alkenes II: Oxidation and Reduction150
- Ch. 10 - Alkynes: Electrophilic Addition and Redox Reactions101
- Ch. 11 - Properties and Synthesis of Alkyl Halides: Radical Reactions108
- Ch. 12 - Substitution and Elimination: Reactions of Haloalkanes172
- Ch. 13 - Alcohols, Ethers and Related Compounds: Substitution and Elimination239
- Ch. 14 - Structural Identification I: Infrared Spectroscopy and Mass Spectrometry54
- Ch. 15 - Structural Identification II: Nuclear Magnetic Resonance Spectroscopy93
- Ch. 16 - Metals in Organic Chemistry48
- Ch. 17 - Carbonyl Addition Reactions: Aldehydes and Ketones45
- Ch. 18 - Nucleophilic Acyl Substitution I: Carboxylic Acids18
- Ch. 19 - Nucleophilic Acyl Substitution II: Carboxylic Acid Derivatives39
- Ch. 20 - Enolates: Carbonyl Addition and Substitution13
- Ch. 21 - Conjugated Systems I: Stability and Addition Reactions56
- Ch. 22 - Conjugated Systems II: Pericyclic Reactions54
- Ch. 23 - Benzene I: Aromatic Stability and Substitution Reactions64
- Ch. 24 - Benzene II: Reactions Influenced by the Aromatic Ring62
- Ch. 25 - Amines: Structure, Reactions, and Synthesis27
- Ch. 26 - Amino Acids, Proteins, and Peptide Synthesis9
- Ch. 27 - Carbohydrates, Nucleic Acids, and Lipids54
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Not the one you use?Change textbook
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Mullins 1st EditionCh. 24 - Benzene II: Reactions Influenced by the Aromatic RingProblem 3
Mullins 1st EditionCh. 24 - Benzene II: Reactions Influenced by the Aromatic RingProblem 3Chapter 23, Problem 3
Provide an arrow-pushing mechanism for the following alkane bromination. [Don't forget to use fishhook arrows to represent the movement of single electrons.]
Verified step by step guidance1
Step 1: Initiation - Begin by homolytic cleavage of the bromine molecule (Br₂) to form two bromine radicals. Use fishhook arrows to show the movement of single electrons from the Br-Br bond to each bromine atom, resulting in two Br• radicals.
Step 2: Propagation - The bromine radical (Br•) abstracts a hydrogen atom from the alkane, forming a hydrogen bromide (HBr) and an alkyl radical. Use a fishhook arrow to show the movement of a single electron from the Br• to the hydrogen atom, and another fishhook arrow to show the movement of the single electron from the C-H bond to the carbon atom, forming the alkyl radical.
Step 3: Propagation - The alkyl radical reacts with another bromine molecule (Br₂), forming the brominated alkane and regenerating a bromine radical. Use fishhook arrows to show the movement of single electrons from the alkyl radical and the Br-Br bond to form the new C-Br bond and regenerate Br•.
Step 4: Termination - Two radicals combine to form a stable molecule, terminating the chain reaction. This can occur between two bromine radicals, two alkyl radicals, or an alkyl radical and a bromine radical. Use fishhook arrows to show the movement of single electrons from each radical to form a covalent bond.
Step 5: Review the mechanism - Ensure that all steps are balanced in terms of electron movement and that the overall reaction results in the bromination of the alkane. Check that all fishhook arrows correctly represent the movement of single electrons throughout the mechanism.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Radical Halogenation
Radical halogenation is a reaction where alkanes react with halogens, such as bromine, under UV light or heat to form haloalkanes. The process involves the formation of radicals, which are highly reactive species with unpaired electrons, and proceeds through initiation, propagation, and termination steps.
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Fishhook Arrows
Fishhook arrows are used in organic chemistry to depict the movement of single electrons during radical reactions. Unlike regular arrows, which show the movement of electron pairs, fishhook arrows indicate the transfer of one electron, essential for illustrating radical mechanisms like alkane bromination.
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Mechanism Steps: Initiation, Propagation, Termination
The mechanism of radical reactions includes three main steps: initiation, where radicals are generated; propagation, where radicals react with stable molecules to form new radicals; and termination, where radicals combine to form stable products. Understanding these steps is crucial for mapping out the arrow-pushing mechanism in alkane bromination.
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Related Practice
Textbook Question
What is the product of the following reaction?
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Textbook Question
Calculate the oxidation number of the indicated atoms in the following reaction.
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Textbook Question
Which haloalkane would you expect to undergo the fastest SN1 reaction? Why?
Textbook Question
What reagent would you use to brominate the allylic carbon of cyclohexene?
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