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

SN1 Reaction

Organic Chemistry

7. Substitution Reactions

SN1 Reaction

Previous problemNext problem

2:05 minutes

Problem 26

Textbook Question

Which reaction would be faster, the one with DMSO as the solvent or the one with ethanol (EtOH)?

Verified step by step guidance

Step 1: Understand the role of the solvent in a chemical reaction. Solvents can influence the rate of a reaction by stabilizing intermediates, affecting nucleophilicity, or altering the reaction mechanism. DMSO (dimethyl sulfoxide) is an aprotic solvent, while ethanol (EtOH) is a protic solvent.

Step 2: Recall the difference between protic and aprotic solvents. Protic solvents, like ethanol, can donate hydrogen bonds and stabilize ions, particularly nucleophiles, by forming hydrogen bonds. Aprotic solvents, like DMSO, do not donate hydrogen bonds and instead stabilize cations, leaving nucleophiles more reactive.

Step 3: Consider the type of reaction. For example, in an SN2 reaction, aprotic solvents like DMSO are preferred because they do not hinder the nucleophile, allowing it to attack the electrophile more effectively. In contrast, protic solvents like ethanol can slow down SN2 reactions by stabilizing the nucleophile through hydrogen bonding.

Step 4: Evaluate the solvent's impact on the reaction mechanism. If the reaction is SN1, protic solvents like ethanol are often better because they stabilize the carbocation intermediate formed during the rate-determining step. Aprotic solvents like DMSO are less effective in stabilizing carbocations, which can slow down SN1 reactions.

Step 5: Conclude that the reaction rate depends on the mechanism (SN1 or SN2) and the solvent's ability to stabilize intermediates or nucleophiles. For an SN2 reaction, DMSO would likely lead to a faster reaction, while for an SN1 reaction, ethanol might be faster. Analyze the specific reaction to determine the mechanism and solvent compatibility.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Solvent Polarity

The polarity of a solvent significantly influences the rate of chemical reactions. DMSO (dimethyl sulfoxide) is a highly polar aprotic solvent, which can stabilize charged intermediates and transition states, often leading to faster reaction rates. In contrast, ethanol is a polar protic solvent that can form hydrogen bonds, which may hinder the reaction rate for certain mechanisms.

Nucleophilicity and Electrophilicity

The reactivity of nucleophiles and electrophiles is crucial in determining reaction rates. In polar aprotic solvents like DMSO, nucleophiles are generally more reactive because they are less solvated compared to those in polar protic solvents like ethanol. This difference can lead to faster reactions in DMSO if the mechanism involves nucleophilic attack.

Reaction Mechanism

The specific mechanism of a reaction (e.g., SN1, SN2, E1, E2) plays a vital role in how solvent choice affects reaction speed. For example, SN2 reactions benefit from polar aprotic solvents that enhance nucleophilicity, while SN1 reactions may be favored in polar protic solvents due to better stabilization of carbocation intermediates. Understanding the mechanism helps predict which solvent will lead to a faster reaction.

Watch next

Master Drawing the SN1 Mechanism with a bite sized video explanation from Johnny

Start learning

Related Videos

Related Practice

Textbook Question

Choose the member of each pair that will react faster by the SN1 mechanism.

e. 2-iodo-2-methylbutane or tert-butyl chloride

f. 2-bromo-2-methylbutane or ethyl iodide

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.

b. What happens to the rate if the concentration of tert-butyl bromide is tripled and the concentration of ethanol is doubled?

c. What happens to the rate if the temperature is raised?

Textbook Question

tert-Butyl chloride undergoes solvolysis in both acetic acid and formic acid. Solvolysis occurs 5000 times faster in one of these two solvents than in the other. In which solvent is solvolysis faster? Explain your answer. (Hint: Formic acid is more polar than acetic acid.)

Textbook Question

Rank the following alkyl halides from most reactive to least reactive in an S_N1 reaction:

2-bromo-2-methylpentane, 2-chloro-2-methylpentane, 3-chloropentane, and 2-iodo-2-methylpentane.

Textbook Question

a. Identify the substitution products that form when 2-bromo-2-methylpropane is dissolved in a mixture of 80% ethanol and 20% water.

b. Explain why the same products are obtained when 2-chloro-2-methylpropane is dissolved in a mixture of 80% ethanol and 20% water.

Textbook Question

Explain why tetrahydrofuran can solvate a positively charged species better than diethyl ether can.

Textbook Question

Two bromoethers are obtained from the reaction of the following alkyl dihalide with methanol. Draw the structures of the ethers.

Textbook Question

In contrast, optically active butan-2-ol does not racemize on treatment with a solution of KOH. Explain why a reaction like that in part (a) does not occur.

Show more practices

Download the Mobile app

Privacy

Do not sell my personal information

Accessibility

Patent notice

Sitemap