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 - Strong Oxidation (Aldaric Acid)

Organic Chemistry

28. Carbohydrates

Monosaccharides - Strong Oxidation (Aldaric Acid)

Previous problemNext problem

1:39 minutes

Problem 59b

Textbook Question

Which of the D-aldotetroses will give optically active aldaric acids on oxidation with HNO₃?

Verified step by step guidance

Identify the structure of d-aldotetroses. Aldotetroses are four-carbon aldoses (monosaccharides with an aldehyde group). The 'd-' designation refers to the configuration of the chiral center farthest from the aldehyde group, which corresponds to the D-glyceraldehyde configuration.

Recall that aldaric acids are formed by oxidizing both the aldehyde group and the terminal primary alcohol group of an aldose to carboxylic acids. This reaction is typically carried out using nitric acid (HNO₃).

Determine the condition for optical activity in aldaric acids. For an aldaric acid to be optically active, it must have at least one chiral center and lack a plane of symmetry (i.e., it must not be meso).

Analyze the d-aldotetroses (D-erythrose and D-threose). Oxidation of D-erythrose produces meso-tartaric acid, which is optically inactive due to its plane of symmetry. Oxidation of D-threose produces an optically active aldaric acid because the resulting molecule lacks a plane of symmetry and retains chirality.

Conclude that D-threose is the d-aldotetrose that will give an optically active aldaric acid upon oxidation with HNO₃, while D-erythrose will not.

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.

D-Aldotetroses

D-Aldotetroses are a class of carbohydrates that contain four carbon atoms and an aldehyde functional group. They can exist in different stereoisomeric forms due to the presence of chiral centers. The two common D-aldotetroses are D-erythrose and D-threose, which differ in the arrangement of hydroxyl groups around their chiral centers.

Optical Activity

Optical activity refers to the ability of a chiral compound to rotate the plane of polarized light. This property arises from the asymmetry of the molecule, which can exist in two enantiomeric forms that are mirror images of each other. Only chiral compounds, such as certain aldoses, can exhibit optical activity, making it a key factor in determining the nature of the products formed during chemical reactions.

Aldaric Acids

Aldaric acids are dicarboxylic acids derived from aldoses through oxidation, where both the aldehyde and the primary alcohol groups are oxidized to carboxylic acids. The formation of aldaric acids from aldoses can lead to optically active products if the starting aldose is chiral. The specific aldaric acid produced depends on the stereochemistry of the original aldose, influencing its optical properties.

Watch next

Master Monosaccharides - Strong Oxidation (Aldaric Acid) with a bite sized video explanation from Johnny

Start learning

Related Videos

Related Practice

Textbook Question

Draw and name the products of nitric acid oxidation of

(a) D-mannose

(b) D-galactose

Textbook Question

a. Name an aldohexose other than D-glucose that is oxidized to D-glucaric acid by nitric acid.

b. What is another name for D-glucaric acid?

Textbook Question

Identify the sugar in each description.

b. A sugar that is not D-altrose forms D-altraric acid when it is oxidized with nitric acid.

Textbook Question

Which of the D-aldopentoses will give optically active aldaric acids on oxidation with HNO₃?

Textbook Question

How many aldaric acids are obtained from the 16 aldohexoses?

Textbook Question

Name another pair of aldohexoses that are oxidized to identical aldaric acids.

Textbook Question

Two sugars, A and B, are known to be glucose and galactose, but it is not certain which one is which. On treatment with nitric acid, A gives an optically inactive aldaric acid, while B gives an optically active aldaric acid. Which sugar is glucose, and which is galactose?

Textbook Question

Draw and name the products of nitric acid oxidation of

(a) D-mannose

(b) D-galactose

Show more practices