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

21. Aldehydes and Ketones: Nucleophilic Addition

Naming Aldehydes

Organic Chemistry

21. Aldehydes and Ketones: Nucleophilic Addition

Naming Aldehydes

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3:21 minutes

Problem 2

Textbook Question

Why are numbers not used to designate the position of the functional group in propanone and butanedione?

Verified step by step guidance

Understand the structure of the compounds: Propanone (commonly known as acetone) has the molecular formula CH₃COCH₃, and butanedione (commonly known as diacetyl) has the molecular formula CH₃COCOCH₃. Both are ketones, meaning they contain a carbonyl group (C=O) bonded to two carbon atoms.

Recall the IUPAC naming rules for ketones: The position of the carbonyl group is indicated by a number if it is necessary to distinguish its location. The numbering starts from the end of the carbon chain closest to the carbonyl group to give it the lowest possible number.

Analyze the structure of propanone: In propanone, the carbonyl group is always located on the second carbon atom because the molecule has only three carbon atoms. Since there is no ambiguity in the position of the carbonyl group, a number is not required in the name.

Analyze the structure of butanedione: In butanedione, there are two carbonyl groups, each located on the second and third carbon atoms of the four-carbon chain. The positions of these groups are fixed and symmetric, so there is no need to specify their locations with numbers in the name.

Conclude the reasoning: Numbers are not used to designate the position of the functional group in propanone and butanedione because the positions of the carbonyl groups are unambiguous and fixed by the structure of the molecules. Including numbers would be redundant in these cases.

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Key Concepts

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

Functional Groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. In organic chemistry, the presence and position of functional groups significantly influence the properties and reactivity of compounds. Understanding functional groups is essential for naming and classifying organic compounds.

IUPAC Nomenclature

The International Union of Pure and Applied Chemistry (IUPAC) nomenclature provides a systematic method for naming organic compounds. According to IUPAC rules, the position of functional groups is indicated by numbers only when necessary for clarity. In cases where the functional group is at a position that is universally understood, such as in propanone and butanedione, numbering is often omitted.

Structural Isomerism

Structural isomerism occurs when compounds have the same molecular formula but different structural arrangements of atoms. In the case of propanone (a ketone) and butanedione (a diketone), the functional groups are positioned in such a way that their locations are inherently clear from the molecular structure. This clarity allows for the omission of numbers in their names, as the functional groups' positions are implied.

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