Textbook Question
Imidazole is a heteroaromatic base. Which nitrogen, a or b, is most basic?
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Ch. 23 - Benzene I: Aromatic Stability and Substitution Reactions
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. 23 - Benzene I: Aromatic Stability and Substitution ReactionsProblem 5b
Mullins 1st EditionCh. 23 - Benzene I: Aromatic Stability and Substitution ReactionsProblem 5bChapter 22, Problem 5b
Suggest an arrow-pushing mechanism that accounts for the formation of the following Lewis acid–Lewis base complexes. Label the Lewis acid and Lewis base in each.
(b) 
Verified step by step guidance1
Step 1: Identify the Lewis acid and Lewis base in the reaction. The Lewis acid is Br⁺ because it is electron-deficient and can accept a pair of electrons. The Lewis base is the alkene because it has a π-electron cloud that can donate electrons.
Step 2: Begin the arrow-pushing mechanism by showing the π-electrons of the alkene attacking the Br⁺. Draw a curved arrow from the π-bond of the alkene to the Br⁺, indicating the donation of electrons.
Step 3: As the alkene donates electrons to Br⁺, a new bond forms between one of the carbon atoms in the alkene and the Br atom. This results in the formation of a carbocation intermediate on the other carbon atom of the alkene.
Step 4: Represent the carbocation intermediate explicitly, showing the positive charge on the carbon atom that did not bond with Br. This step is crucial for understanding the stability of the intermediate.
Step 5: Conclude the mechanism by showing the final Lewis acid–Lewis base complex, where the Br atom is bonded to one of the carbon atoms, and the other carbon atom carries a positive charge. Ensure the structure reflects the correct connectivity and charge distribution.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Lewis Acids and Bases
Lewis acids are species that can accept an electron pair, while Lewis bases are species that can donate an electron pair. In the provided reaction, the bromonium ion (Br+) acts as a Lewis acid, accepting electron density from the alkene, which serves as the Lewis base. Understanding these definitions is crucial for analyzing acid-base reactions in organic chemistry.
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The Lewis definition of acids and bases.
Arrow-Pushing Mechanism
The arrow-pushing mechanism is a method used to illustrate the movement of electrons during chemical reactions. Arrows indicate the direction of electron flow, showing how bonds are formed or broken. In the given reaction, arrows would depict the donation of an electron pair from the alkene to the Br+ ion, leading to the formation of a new bond.
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Formation of Carbocations
Carbocations are positively charged carbon species that can form during reactions involving Lewis acids. In the context of the provided reaction, the interaction between the alkene and Br+ can lead to the formation of a carbocation intermediate. Understanding carbocation stability and reactivity is essential for predicting the outcome of many organic reactions.
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Related Practice
Textbook Question
If Kekulé's original hypothesis had been correct and benzene was really an equilibrium between two structures, how many distinct isomers would exist for 1,2-dichlorobenzene?
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Textbook Question
The average C―C single bond length is 1.53 Å, and the average C=C double bond length is 1.31 Å. All of the C―C bonds in benzene are the same length (1.42 Å). Explain.
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Textbook Question
Suggest an arrow-pushing mechanism that accounts for the formation of the following Lewis acid–Lewis base complexes. Label the Lewis acid and Lewis base in each.
(a)
Textbook Question
Draw resonance structures to identify which of the following is the more stable carbocation.
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