Textbook Question
You were told in [SECTION 7.11] that is best to use a methyl halide or a primary alkyl halide for the reaction of an acetylide ion with an alkyl halide. Explain why this is so.
2
views
Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides
Bruice8th EditionOrganic ChemistryISBN: 9780135213711
Not the one you use?Change textbookSelect a different textbook
Table of contents
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 1)31
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 2)65
- Ch. 2 - Acids and Bases: Central to Understanding Organic Chemistry84
- Ch. 3 - An Introduction to Organic Compounds:Nomenclature, Physical Properties, and Structure183
- Ch. 4 - Isomers: The Arrangement of Atoms in Space121
- Ch. 5 - Alkenes: Structure, Nomenclature, and an Introduction to Reactivity • Thermodynamics and Kinetics83
- Ch. 6 - The Reactions of Alkenes • The Stereochemistry of Addition Reactions175
- Ch. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis119
- Ch. 8 - Delocalized Electrons: Their Effect on Stability, pKa, and the Products of a Reaction • Aromaticity and Electronic Effects: An Introduction to the Reactions of Benzene148
- Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides212
- Ch. 10 - Reactions of Alcohols, Ethers, Epoxides, Amines, and Sulfur-Containing Compounds131
- Ch. 11 - Organometallic Compounds60
- Ch. 12 - Radicals90
- Ch. 13 - Mass Spectrometry; Infrared Spectroscopy; UV/Vis Spectroscopy62
- Ch. 14 - NMR Spectroscopy95
- Ch. 15 - Reactions of Carboxylic Acids and Carboxylic Acid Derivatives123
- Ch. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid Derivatives141
- Ch. 17 - Reactions at the Alpha-Carbon101
- Ch. 18 - Reactions of Benzene and Substituted Benzenes144
- Ch. 19 - More About Amines • Reactions of Heterocyclic Compounds49
- Ch. 20 - The Organic Chemistry of Carbohydrates80
- Ch. 21 - Amino Acids, Peptides, and Proteins57
- Ch. 22 - Catalysis in Organic Reactions and in Enzymatic Reactions35
- Ch. 23 - The Organic Chemistry of the Coenzymes—Compounds Derived from Vitamins1
- Ch. 28 - Pericyclic Reactions58
All textbooks
Bruice 8th EditionCh. 9 - Substitution and Elimination Reactions of Alkyl HalidesProblem 39c
Bruice 8th EditionCh. 9 - Substitution and Elimination Reactions of Alkyl HalidesProblem 39cChapter 10, Problem 39c
Which reacts faster in an SN1 reaction?
Verified step by step guidance1
Step 1: Understand the SN1 reaction mechanism. SN1 reactions proceed via a two-step mechanism: (1) formation of a carbocation intermediate by the departure of the leaving group, and (2) nucleophilic attack on the carbocation. The rate-determining step is the formation of the carbocation, so the stability of the carbocation is a key factor in determining the reaction rate.
Step 2: Evaluate the structure of the reactants. Identify the type of carbon (primary, secondary, or tertiary) attached to the leaving group. Tertiary carbocations are more stable than secondary, which are more stable than primary, due to hyperconjugation and inductive effects.
Step 3: Consider the leaving group. A good leaving group facilitates the formation of the carbocation. Leaving groups such as halides (e.g., Cl⁻, Br⁻, I⁻) or sulfonates (e.g., tosylate) are commonly involved in SN1 reactions. Compare the leaving groups of the reactants to determine which one is better.
Step 4: Assess the solvent. SN1 reactions are favored in polar protic solvents (e.g., water, alcohols) because they stabilize the carbocation intermediate and the leaving group. Check if the reaction conditions include such solvents.
Step 5: Combine all factors. Based on the stability of the carbocation, the quality of the leaving group, and the solvent conditions, determine which reactant will react faster in the SN1 reaction. The reactant that forms the most stable carbocation and has the best leaving group will typically react faster.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
SN1 Reaction Mechanism
The SN1 (Substitution Nucleophilic Unimolecular) reaction mechanism involves two main steps: the formation of a carbocation intermediate and the subsequent nucleophilic attack. The rate of an SN1 reaction depends primarily on the stability of the carbocation formed, as the first step is the rate-determining step. More stable carbocations, such as tertiary carbocations, react faster than less stable ones.
Recommended video:
Guided course
10:49
Drawing the SN1 Mechanism
Carbocation Stability
Carbocation stability is influenced by the degree of alkyl substitution and resonance. Tertiary carbocations are the most stable due to hyperconjugation and inductive effects from surrounding alkyl groups. In contrast, primary carbocations are the least stable, making them less likely to form in SN1 reactions. Understanding the stability of carbocations is crucial for predicting the reactivity in SN1 mechanisms.
Recommended video:
Guided course
05:58Determining Carbocation Stability
Nucleophilicity
Nucleophilicity refers to the ability of a nucleophile to donate an electron pair to an electrophile. In SN1 reactions, the nucleophile attacks the carbocation after its formation. While the strength of the nucleophile can influence the overall reaction rate, in SN1 reactions, the rate is primarily determined by the stability of the carbocation rather than the nucleophile's strength.
Recommended video:
Guided course
08:27Nucleophilic Addition
Related Practice
Textbook Question
Draw the substitution and elimination products for the following reactions, showing the configuration of each product:
c. 1-chloro-1-methylcyclohexane + CH3O−
d. 1-chloro-1-methylcyclohexane + CH3OH
2
views
Textbook Question
Which reacts faster in an SN2 reaction?
1
views
Textbook Question
Explain why only a substitution product and no elimination product is obtained when the following compound reacts with sodium methoxide:
2
views
Textbook Question
Which reacts faster in an E1 reaction?
2
views
Textbook Question
How does the ratio of substitution product to elimination product formed from the reaction of propyl bromide with CH3O− in methanol change if the nucleophile is changed to CH3S−?
2
views