Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

7. Substitution Reactions

SN2 Reaction

Organic Chemistry

7. Substitution Reactions

SN2 Reaction

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4:12 minutes

Problem 14b

Textbook Question

Predict the major products of the following substitutions.
b.

Verified step by step guidance

Identify the type of reaction: This is a nucleophilic substitution reaction where sodium acetylide (HC≡C:- Na+) acts as a nucleophile, and 1-chlorobutane (CH3CH2CH2CH2Cl) is the alkyl halide.

Determine the mechanism: Since 1-chlorobutane is a primary alkyl halide, the reaction will proceed via the SN2 mechanism. In an SN2 reaction, the nucleophile attacks the electrophilic carbon directly, leading to a one-step displacement of the leaving group (Cl⁻).

Analyze the nucleophile: Sodium acetylide (HC≡C:- Na+) is a strong nucleophile due to the negatively charged carbon in the acetylide ion. This makes it highly reactive toward electrophilic carbons.

Describe the reaction: The acetylide ion (HC≡C:-) will attack the carbon atom bonded to the chlorine in 1-chlorobutane (CH3CH2CH2CH2Cl). This results in the displacement of the chloride ion (Cl⁻) and the formation of a new carbon-carbon bond between the acetylide ion and the butyl group.

Write the product: The major product will be a terminal alkyne with the structure HC≡C-CH2CH2CH2CH3, where the acetylide ion has replaced the chlorine atom in 1-chlorobutane.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Nucleophilic Substitution

Nucleophilic substitution is a fundamental reaction in organic chemistry where a nucleophile attacks an electrophile, resulting in the replacement of a leaving group. In this case, sodium acetylide (HC≡C:- Na+) acts as the nucleophile, targeting the carbon atom bonded to the chlorine in 1-chlorobutane. Understanding the mechanism of this reaction, whether it follows an SN1 or SN2 pathway, is crucial for predicting the major products.

Alkyne Reactivity

Alkynes, such as sodium acetylide, are highly reactive due to the presence of a triple bond, which can participate in various reactions, including nucleophilic substitutions. The terminal alkyne (HC≡C:-) has a negative charge on the carbon, making it a strong nucleophile. Recognizing the reactivity of alkynes helps in predicting how they will interact with alkyl halides like 1-chlorobutane.

Leaving Groups

A leaving group is an atom or group that can depart from the parent molecule during a chemical reaction, facilitating the formation of new bonds. In the context of the reaction with 1-chlorobutane, the chloride ion (Cl-) is the leaving group. The stability of the leaving group significantly influences the reaction's rate and the formation of products, making it essential to consider when predicting the outcome of nucleophilic substitutions.

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