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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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 41(a)
Mullins 1st EditionCh. 5 - Chemical Reaction Analysis: Thermodynamics and KineticsProblem 41(a)Chapter 4, Problem 41(a)
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):
Verified step by step guidance1
Understand the concept of substitution reactions: In this problem, we are replacing a hydrogen atom (H) with a deuterium atom (D). Deuterium is an isotope of hydrogen, meaning it has the same chemical properties but a different mass due to an additional neutron.
Identify the number of hydrogens available for substitution: Count the total number of hydrogen atoms in the molecule that can be replaced by deuterium. This will help determine the statistical distribution of products.
Consider the statistical probability: Since the substitution is random and there is no preference for one hydrogen over another, the ratio of products will depend on the number of hydrogens available for substitution. For example, if there are 4 hydrogens, each hydrogen has an equal probability of being replaced by deuterium.
Calculate the ratio of products: The ratio of products will be proportional to the number of hydrogens available for substitution. For instance, if there are 4 hydrogens, the statistical ratio of products would be 1:1:1:1 for each possible substitution site.
Summarize the reasoning: The ratio of products is based purely on the statistical likelihood of substitution at each hydrogen position, assuming no other factors (such as steric hindrance or electronic effects) influence the reaction.
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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 are a fundamental type of chemical reaction where one atom or group of atoms in a molecule is replaced by another atom or group. In organic chemistry, these reactions often involve the replacement of a functional group, such as a hydrogen atom, with another atom or group, like deuterium. Understanding the nature of these reactions is crucial for predicting product ratios.
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Recognizing Substitution Reactions.
Statistical Distribution of Products
In the context of substitution reactions, a statistical distribution refers to the likelihood of different products forming based on the number of available sites for substitution. When considering a reaction where a hydrogen atom is replaced by deuterium, the expectation of product ratios can be derived from the relative abundance of the reactants and the probability of substitution occurring at each site.
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Isotope Effects
Isotope effects occur when the presence of different isotopes of an element, such as hydrogen (H) and deuterium (D), influences the rate or outcome of a chemical reaction. In substitution reactions, the heavier isotope (D) can lead to different reaction kinetics compared to H, affecting the product distribution. This concept is essential for understanding how isotopic substitution can alter reaction pathways and product ratios.
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Related Practice
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?
(b) Replacing a hydrogen (H) with bromine (Br):
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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
For each pair of reactions, predict which will happen more quickly.
[For (a) and (b), think about the stability of the bases involved.]
(a)
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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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