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

28. Carbohydrates

Monosaccharides - Weak Oxidation (Aldonic Acid)

Organic Chemistry

28. Carbohydrates

Monosaccharides - Weak Oxidation (Aldonic Acid)

Previous problemNext problem

Problem 23

Textbook Question

Predict the products obtained when d-galactose reacts with each reagent.(a) Br2 and H2O

Verified step by step guidance

Identify the functional groups present in D-galactose. D-galactose is an aldose sugar, meaning it contains an aldehyde group (-CHO) at the anomeric carbon and multiple hydroxyl (-OH) groups.

Understand the reactivity of Br₂ in H₂O. Bromine in water is a mild oxidizing agent that selectively oxidizes aldehydes to carboxylic acids without affecting the hydroxyl groups.

Write the reaction mechanism. The aldehyde group (-CHO) of D-galactose reacts with Br₂ in H₂O to form a carboxylic acid group (-COOH), converting the sugar into its corresponding aldonic acid.

Determine the product. The oxidation of the aldehyde group in D-galactose results in the formation of D-galactonic acid, where the aldehyde is replaced by a carboxylic acid group.

Verify the stereochemistry. Since the reaction only affects the aldehyde group and does not alter the stereochemistry of the other chiral centers, the stereochemistry of the sugar remains unchanged.

Verified video answer for a similar problem:

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

Play a video:

Was this helpful?

Key Concepts

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

D-Galactose Structure

D-galactose is a six-carbon aldose sugar with a specific stereochemistry. It contains an aldehyde functional group and multiple hydroxyl groups, which are crucial for its reactivity. Understanding its structure helps predict how it will interact with reagents, particularly in oxidation and substitution reactions.

Oxidation Reactions

Oxidation reactions involve the loss of electrons or an increase in oxidation state, often resulting in the conversion of alcohols to carbonyl compounds. In the case of D-galactose reacting with Br2 and H2O, the aldehyde group can be oxidized to a carboxylic acid, leading to specific product formation. Recognizing the nature of the oxidizing agent is essential for predicting the outcome.

Halogenation of Sugars

Halogenation refers to the introduction of halogen atoms into organic compounds. When D-galactose reacts with bromine in the presence of water, it can undergo bromination at the hydroxyl groups or the aldehyde carbon, leading to the formation of brominated sugar derivatives. Understanding the mechanism of halogenation is key to predicting the products of this reaction.

Watch next

Master Monosaccharides - Weak Oxidation (Aldonic Acid) with a bite sized video explanation from Johnny

Start learning