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

1. A Review of General Chemistry

Degrees of Unsaturation

Organic Chemistry

1. A Review of General Chemistry

Degrees of Unsaturation

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Problem 1b

Textbook Question

Given the molecular formula, calculate the index of hydrogen deficiency.
(b) C₄H₉ON

Verified step by step guidance

Step 1: Understand the concept of the Index of Hydrogen Deficiency (IHD). The IHD, also known as the degree of unsaturation, indicates the number of rings, double bonds, or triple bonds in a molecule. Each degree of unsaturation corresponds to the loss of two hydrogens compared to a fully saturated molecule.

Step 2: Use the formula for IHD: IHD = (2C + 2 + N - H - X) / 2, where C is the number of carbons, H is the number of hydrogens, N is the number of nitrogens, and X is the number of halogens (if present). Oxygen (O) does not affect the IHD calculation.

Step 3: Substitute the values from the molecular formula C₄H₉ON into the IHD formula. Here, C = 4, H = 9, N = 1, and there are no halogens (X = 0). Oxygen is ignored in the calculation.

Step 4: Perform the calculation step-by-step. First, calculate the numerator: (2 × 4) + 2 + 1 - 9 - 0. Then divide the result by 2 to determine the IHD.

Step 5: Interpret the result. If the IHD is 0, the molecule is fully saturated (no rings or double/triple bonds). If the IHD is 1 or higher, it indicates the presence of unsaturation (e.g., a ring or a double bond).

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Key Concepts

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

Index of Hydrogen Deficiency (IHD)

The Index of Hydrogen Deficiency (IHD) is a measure of the degree of unsaturation in a molecular formula. It indicates the number of rings and/or multiple bonds present in a compound. Each double bond or ring contributes one to the IHD, while each triple bond contributes two. The formula for calculating IHD is IHD = (2C + 2 + N - H - X) / 2, where C is the number of carbons, N is the number of nitrogens, H is the number of hydrogens, and X is the number of halogens.

Molecular Formula Interpretation

A molecular formula provides the number and types of atoms in a molecule, but does not indicate the structure. In the case of C₄H₉ON, the formula indicates four carbon atoms, nine hydrogen atoms, one oxygen atom, and one nitrogen atom. Understanding how to interpret this formula is crucial for calculating the IHD, as it allows for the identification of the elements involved and their contributions to the overall saturation of the molecule.

Unsaturation in Organic Compounds

Unsaturation refers to the presence of double or triple bonds in organic compounds, which affects their reactivity and physical properties. Compounds with higher unsaturation typically have lower hydrogen counts relative to their carbon counts. Recognizing the implications of unsaturation is essential for predicting the behavior of organic molecules, including their stability and potential reactions, which is directly related to the calculation of the IHD.

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