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

Substitution Comparison

Organic Chemistry

7. Substitution Reactions

Substitution Comparison

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5:37 minutes

Problem 38a

Textbook Question

When tert-butyl bromide is heated with an equal amount of ethanol in an inert solvent, one of the products is ethyl tert-butyl ether.
a. What happens to the reaction rate if the concentration of ethanol is doubled?

Verified step by step guidance

Step 1: Recognize the type of reaction occurring. The formation of ethyl tert-butyl ether from tert-butyl bromide and ethanol suggests an SN1 reaction mechanism, as tert-butyl bromide is a tertiary alkyl halide, favoring carbocation formation.

Step 2: Understand the rate-determining step in an SN1 reaction. The rate-determining step is the formation of the carbocation intermediate, which depends only on the concentration of tert-butyl bromide and not on the concentration of ethanol.

Step 3: Analyze the role of ethanol in the reaction. Ethanol acts as a nucleophile, attacking the carbocation formed in the rate-determining step to produce the ether. However, its concentration does not affect the rate of carbocation formation.

Step 4: Predict the effect of doubling the ethanol concentration. Since the reaction rate in an SN1 mechanism is independent of the nucleophile concentration, doubling the ethanol concentration will not change the reaction rate.

Step 5: Conclude the relationship between ethanol concentration and reaction rate. The reaction rate remains unchanged when the ethanol concentration is doubled because the rate-determining step depends solely on the concentration of tert-butyl bromide.

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Key Concepts

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

Nucleophilic Substitution Reactions

Nucleophilic substitution reactions involve the replacement of a leaving group in a molecule by a nucleophile. In this case, ethanol acts as a nucleophile that attacks the tert-butyl bromide, leading to the formation of ethyl tert-butyl ether. Understanding the mechanism of these reactions, whether they proceed via an SN1 or SN2 pathway, is crucial for predicting how changes in reactant concentrations affect the reaction rate.

Reaction Rate and Concentration

The rate of a chemical reaction is often influenced by the concentration of the reactants. According to the rate law, if the concentration of a reactant is increased, the reaction rate typically increases as well. In this scenario, doubling the concentration of ethanol would likely increase the rate of the reaction, assuming that ethanol is involved in the rate-determining step.

Inert Solvent Effects

Inert solvents are used in reactions to provide a medium that does not participate in the reaction itself. They can influence the reaction rate by stabilizing charged intermediates or transition states. In the case of the reaction between tert-butyl bromide and ethanol, the choice of inert solvent can affect the solvation of the reactants and products, thereby impacting the overall reaction kinetics.

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