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

12. Alcohols, Ethers, Epoxides and Thiols

Alcohol Nomenclature

Organic Chemistry

12. Alcohols, Ethers, Epoxides and Thiols

Alcohol Nomenclature

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2:28 minutes

Problem 34b

Textbook Question

Predict which member of each pair is more acidic, and explain the reasons for your predictions.
b. cyclohexanol or cyclohexanethiol

Verified step by step guidance

Step 1: Understand the concept of acidity. Acidity is determined by the ability of a compound to donate a proton (H⁺). The stability of the conjugate base formed after losing the proton plays a key role in determining acidity. A more stable conjugate base corresponds to a stronger acid.

Step 2: Compare the functional groups in cyclohexanol and cyclohexanethiol. Cyclohexanol contains an -OH group, while cyclohexanethiol contains an -SH group. Both groups can lose a proton to form their respective conjugate bases: cyclohexoxide (C₆H₁₁O⁻) and cyclohexanethiolate (C₆H₁₁S⁻).

Step 3: Analyze the electronegativity of oxygen and sulfur. Oxygen is more electronegative than sulfur, meaning it can better stabilize the negative charge on the conjugate base. This makes the conjugate base of cyclohexanol (C₆H₁₁O⁻) more stable than the conjugate base of cyclohexanethiol (C₆H₁₁S⁻).

Step 4: Consider the bond strength between the hydrogen atom and the heteroatom (O or S). The O-H bond in cyclohexanol is stronger than the S-H bond in cyclohexanethiol, making it easier for cyclohexanethiol to lose a proton compared to cyclohexanol.

Step 5: Conclude based on the above analysis. Cyclohexanethiol is more acidic than cyclohexanol because its conjugate base (C₆H₁₁S⁻) is less stable, and the S-H bond is weaker, allowing for easier proton donation.

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Key Concepts

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

Acidity and pKa

Acidity in organic chemistry refers to the tendency of a compound to donate a proton (H+). The strength of an acid is often measured by its pKa value; lower pKa values indicate stronger acids. Understanding the pKa helps predict which compound in a pair is more acidic, as the one with the lower pKa will more readily donate a proton.

Functional Groups and Their Effects

Different functional groups influence the acidity of a compound due to their electronic properties. For instance, alcohols (like cyclohexanol) have a hydroxyl (-OH) group, while thiols (like cyclohexanethiol) have a sulfhydryl (-SH) group. The electronegativity and size of the atoms involved can affect the stability of the conjugate base formed after deprotonation, impacting acidity.

Inductive Effect

The inductive effect refers to the electron-withdrawing or electron-donating influence of substituents on a molecule. In the case of cyclohexanol and cyclohexanethiol, the sulfur atom in thiols is larger and less electronegative than oxygen, which can lead to a weaker stabilization of the conjugate base. This difference in stabilization can help determine which compound is more acidic.

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