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

6:25 minutes

Problem 34a,b

Textbook Question

Predict the compound in each pair that will undergo solvolysis (in aqueous ethanol) more rapidly.
(a) (CH₃CH₂)₂CH—Cl or (CH₃)₃C—Cl
(b)

Verified step by step guidance

Step 1: Understand the concept of solvolysis. Solvolysis is a nucleophilic substitution reaction where the solvent acts as the nucleophile. The rate of solvolysis depends on the stability of the carbocation intermediate formed during the reaction. Tertiary carbocations are more stable than secondary or primary carbocations due to hyperconjugation and inductive effects.

Step 2: Analyze part (a) of the problem. Compare (CH3CH2)2CH—Cl and (CH3)3C—Cl. The first compound has a secondary alkyl chloride, while the second compound has a tertiary alkyl chloride. Since tertiary carbocations are more stable, (CH3)3C—Cl will undergo solvolysis more rapidly.

Step 3: Analyze part (b) of the problem. Compare the two structures provided in the image. For the first pair in part B, the compound with the allylic bromide (Br attached to a carbon adjacent to a double bond) will undergo solvolysis more rapidly due to the resonance stabilization of the allylic carbocation. For the second pair, the compound with the tertiary bromide will undergo solvolysis more rapidly due to the stability of the tertiary carbocation.

Step 4: Consider the second image for part (b). Compare the linear alkyl chloride and the branched alkyl chloride. The branched alkyl chloride forms a secondary carbocation upon solvolysis, which is more stable than the primary carbocation formed by the linear alkyl chloride. Thus, the branched alkyl chloride will undergo solvolysis more rapidly.

Step 5: Summarize the reasoning. The rate of solvolysis is determined by the stability of the carbocation intermediate. Tertiary carbocations are the most stable, followed by secondary carbocations, and then primary carbocations. Additionally, resonance effects, such as those in allylic carbocations, can further stabilize the intermediate and increase the rate of solvolysis.

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.

Solvolysis

Solvolysis is a type of nucleophilic substitution reaction where a solvent, typically water or an alcohol, acts as the nucleophile. In organic chemistry, it often involves the breaking of a carbon-halogen bond, leading to the formation of a carbocation intermediate. The rate of solvolysis can be influenced by the stability of the carbocation formed, with more stable carbocations undergoing solvolysis more rapidly.

Carbocation Stability

Carbocation stability is a crucial concept in organic chemistry, as it determines the reactivity of compounds in solvolysis reactions. Carbocations are positively charged carbon species, and their stability increases with the degree of substitution: tertiary (3°) carbocations are more stable than secondary (2°), which are more stable than primary (1°). This stability is due to hyperconjugation and inductive effects from surrounding alkyl groups, which can help stabilize the positive charge.

Nucleophilicity of Solvents

The nucleophilicity of solvents plays a significant role in solvolysis reactions. In aqueous ethanol, the solvent can act as a nucleophile, attacking the electrophilic carbon in the substrate. The strength of the nucleophile affects the reaction rate; stronger nucleophiles will lead to faster solvolysis. Additionally, the solvent's ability to stabilize the transition state and the carbocation intermediate can also influence the overall reaction kinetics.

Watch next

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

Start learning

Related Videos

Related Practice

Textbook Question

A reluctant first-order substrate can be forced to ionize by adding some silver nitrate (one of the few soluble silver salts) to the reaction. Silver ion reacts with the halogen to form a silver halide (a highly exothermic reaction), generating the cation of the alkyl group.

Give mechanisms for the following silver-promoted rearrangements.

(a)

Textbook Question

Propose a mechanism involving a hydride shift or an alkyl shift for each solvolysis reaction. Explain how each rearrangement forms a more stable intermediate.

Hint: Most rearrangements convert 2° (or incipient 1°) carbocations to 3° or resonance-stabilized carbocations.

(b)

Textbook Question

Give the S_N1 mechanism for the formation of 2-ethoxy-3-methylbutane, the unrearranged product in this reaction.

Textbook Question

Propose an S_N1 mechanism for the solvolysis of 3-bromo-2,3-dimethylpentane in ethanol.

Textbook Question

Choose the member of each pair that will react faster by the S_N1 mechanism.

a. 1-bromopropane or 2-bromopropane

b. 2-bromo-2-methylbutane or 2-bromo-3-methylbutane

Textbook Question

Furfuryl chloride can undergo substitution by both S_N2 and S_N1 mechanisms. Because it is a 1° alkyl halide, we expect S_N2 but not S_N1 reactions. Draw a mechanism for the S_N1 reaction shown below, paying careful attention to the structure of the intermediate. How can this primary halide undergo S_N1 reactions?