Textbook Question
The radical fluorination of 2-methyl propane resulted in a 14:86 ratio of products.
(a) On the basis of this ratio, calculate the relative reactivity of 1° and 3° C―H bonds in the radical fluorination.
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Ch. 5 - Chemical Reaction Analysis: Thermodynamics and Kinetics
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. 5 - Chemical Reaction Analysis: Thermodynamics and KineticsProblem 41b
Mullins 1st EditionCh. 5 - Chemical Reaction Analysis: Thermodynamics and KineticsProblem 41bChapter 4, Problem 41b
The following are all substitution reactions, two of which we study in later chapters. With no knowledge of mechanism, what would you expect the ratio of products to be for each reaction, based on a random statistical distribution?
(b) Replacing a hydrogen (H) with bromine (Br):
Verified step by step guidance1
Step 1: Identify the type of reaction. This is a substitution reaction where a hydrogen atom on the benzene ring is replaced by bromine (Br). The reaction is expected to follow a random statistical distribution since no specific mechanism is provided.
Step 2: Analyze the structure of the molecule. The benzene ring has three distinct positions for substitution: ortho (adjacent to the methyl group), meta (one position away from the methyl group), and para (opposite to the methyl group). These positions are labeled as A, B, and C in the image.
Step 3: Count the number of hydrogens available for substitution at each position. The ortho positions (A) have two hydrogens, the meta positions (B) have two hydrogens, and the para position (C) has one hydrogen.
Step 4: Calculate the statistical ratio of products based on the number of hydrogens available for substitution. Since there are 2 hydrogens at ortho, 2 at meta, and 1 at para, the ratio of products will be proportional to these numbers: 2:2:1.
Step 5: Conclude that the expected ratio of products (A:B:C) based on random statistical distribution is 2:2:1, assuming no preference for any specific position due to electronic or steric effects.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Substitution Reactions
Substitution reactions involve the replacement of one atom or group in a molecule with another atom or group. In organic chemistry, these reactions are common in aromatic compounds, where a hydrogen atom can be replaced by a halogen, such as bromine or chlorine. Understanding the nature of these reactions is crucial for predicting product ratios based on the stability and reactivity of the intermediates formed.
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Recognizing Substitution Reactions.
Statistical Distribution of Products
In the context of substitution reactions, statistical distribution refers to the likelihood of forming different products based on the number of available reactive sites and the symmetry of the molecule. For example, if a molecule has multiple equivalent positions for substitution, the products will form in a ratio that reflects the number of ways each product can be generated, assuming no preference for any specific site.
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Mechanism of Bromination
The mechanism of bromination in aromatic compounds typically involves the formation of a bromonium ion intermediate, which can lead to different substitution products depending on the orientation of the substituents already present on the aromatic ring. Understanding this mechanism helps predict the distribution of products, as certain positions may be more favorable for substitution due to electronic effects or steric hindrance.
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Related Practice
Textbook Question
For each pair of reactions, predict which will happen more quickly. [For (c) and (d), the more substituted carbocation is more stable due to hyperconjugation.]
(c)
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Textbook Question
Through the course of this chapter, we have discussed only alkane chlorination and bromination, yet there are two other halogens we have not discussed.
(b) Is radical iodination a favorable reaction? Do you expect it to be selective? Show your calculations.
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Textbook Question
Given the ratio of products obtained in the bromination of propane, calculate the relative reactivity of a 1° C–H bond to a 2° C–H bond under these conditions.
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Textbook Question
The following are all substitution reactions, two of which we study in later chapters. With no knowledge of mechanism, what would you expect the ratio of products to be for each reaction, based on a random statistical distribution?
(a) Replacing a hydrogen (H) with deuterium (D):
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Textbook Question
The following are all substitution reactions, two of which we study in later chapters. With no knowledge of mechanism, what would you expect the ratio of products to be for each reaction, based on a random statistical distribution?
(a) Replacing a hydrogen (H) with chlorine (Cl):
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