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

10. Addition Reactions

Dihydroxylation

Organic Chemistry

10. Addition Reactions

Dihydroxylation

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Problem 22d

Textbook Question

Which of molecules A–D would you expect to give a positive permanganate test? That is, which would result in a purple KMnO₄ solution turning brown?
(d)

Verified step by step guidance

Step 1: Understand the permanganate test. The permanganate test is used to identify the presence of unsaturated compounds, such as alkenes or alkynes, or functional groups that can be oxidized, such as alcohols or aldehydes. A positive test results in the purple KMnO₄ solution turning brown due to the formation of MnO₂.

Step 2: Analyze the structure of the molecule provided. The molecule contains a hydroxyl group (-OH) attached to a carbon adjacent to a ketone group (C=O). This is a beta-hydroxy ketone structure.

Step 3: Determine if the functional groups present can be oxidized by KMnO₄. The hydroxyl group (-OH) is capable of being oxidized by KMnO₄ under appropriate conditions, which could lead to a positive permanganate test.

Step 4: Consider the cyclic structure. The cyclohexane ring in the molecule is saturated and does not contain double or triple bonds, so it will not react with KMnO₄. The reactivity is focused on the hydroxyl group.

Step 5: Conclude that the molecule is likely to give a positive permanganate test due to the presence of the oxidizable hydroxyl group (-OH). The purple KMnO₄ solution would turn brown as the hydroxyl group is oxidized.

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Key Concepts

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

Permanganate Test

The permanganate test is a qualitative analysis used to detect the presence of alkenes and certain other functional groups in organic compounds. When an alkene is present, the purple color of potassium permanganate (KMnO₄) is reduced to brown manganese dioxide (MnO₂), indicating a reaction. This test is particularly useful for identifying unsaturation in organic molecules.

Oxidation of Alcohols

Alcohols can undergo oxidation reactions, where they are converted into carbonyl compounds such as aldehydes or ketones. The permanganate test can also indicate the presence of primary and secondary alcohols, as they can be oxidized to aldehydes and ketones, respectively. Tertiary alcohols, however, do not react in this manner, making this concept crucial for interpreting the test results.

Functional Groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. In the context of the permanganate test, the presence of double bonds (alkenes) or hydroxyl groups (alcohols) can significantly influence the outcome of the test. Understanding the functional groups present in the molecules A-D is essential for predicting their reactivity with KMnO₄.

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Related Practice

Textbook Question

At the beginning of Chapter 9, we stated that after finishing Chapters 8 and 9, we would have the ability to make a large variety of functional groups using related reactions. Show the reagent(s) necessary to convert 1-isobutylcyclohexene into the following molecules.

(d)

Textbook Question

The concertedness of the OsO₄ reaction results in both oxygens being added to the same face of the molecule (i.e., syn addition). How might these conditions be modified in order to prepare a trans-diol?

Textbook Question

Predict the product(s) of each of the following reactions, making sure to indicate the relative stereochemical outcome. Indicate any racemic mixtures by drawing both enantiomers.

(b)

Textbook Question

When using a terminal alkene under the conditions shown here, explain why it is unnecessary to show the relative stereochemical outcome in the product.

Textbook Question

Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (v) mCPBA; (vi) 1. OsO₄ 2. NaHSO₃.

(e)

Textbook Question

Draw the organic products you would expect to isolate from the following reactions (after hydrolysis).

(n)

Textbook Question

Predict the product(s) that would result when the following molecules are allowed to react under the following conditions: (iv) 1. OsO₄ 2. NaHSO₃. If there is no reaction, write 'no reaction.'

(a)

Textbook Question

Suggest a reagent and a reactant that could be combined to make each of the following alcohols.

(b)

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