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

Previous problemNext problem

5:44 minutes

Problem 21c

Textbook Question

Which of the following bases would favorably deprotonate a hydroxyl group?
(c) NaCN

Verified step by step guidance

Identify the pKa of the hydroxyl group. Hydroxyl groups typically have a pKa around 15-18, indicating the strength of the acid.

Determine the pKa of the conjugate acid of the base in question, NaCN. The conjugate acid of CN⁻ is HCN, which has a pKa of approximately 9.2.

Compare the pKa values: A base can deprotonate an acid if the pKa of the conjugate acid of the base is lower than the pKa of the acid being deprotonated.

Since the pKa of HCN (9.2) is lower than the pKa of the hydroxyl group (15-18), CN⁻ is a strong enough base to deprotonate the hydroxyl group.

Conclude that NaCN, which provides CN⁻ ions, can favorably deprotonate a hydroxyl group due to the relative acidity of HCN compared to the hydroxyl group.

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.

Acid-Base Chemistry

Acid-base chemistry involves the transfer of protons between molecules. A base is a substance that can accept protons, while an acid is a substance that can donate protons. Understanding the strength of acids and bases is crucial for predicting the outcome of deprotonation reactions, where a base removes a proton from an acid.

pKa and Basicity

The pKa value of a compound indicates its acidity; lower pKa values correspond to stronger acids. Basicity refers to the ability of a base to accept protons. A base will favorably deprotonate a hydroxyl group if it is strong enough to overcome the hydroxyl's pKa, meaning the base must have a higher affinity for protons than the hydroxyl group.

Nucleophilicity of Cyanide Ion

The cyanide ion (CN-) is a strong nucleophile due to its negative charge and small size, which allows it to effectively attack electrophilic centers. In the context of deprotonation, CN- can act as a base, accepting protons from hydroxyl groups if the reaction conditions favor its basic properties over its nucleophilic tendencies.