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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3:16 minutes

Problem 58a

Textbook Question

Calculate the index of hydrogen deficiency for the following molecular formulas and structures.
(a)

Verified step by step guidance

Step 1: Understand the concept of the Index of Hydrogen Deficiency (IHD). The IHD is a measure of the degree of unsaturation in a molecule, indicating the number of rings, double bonds, or triple bonds present. It is calculated using the formula: IHD = (2C + 2 - H + N - X)/2, where C = number of carbons, H = number of hydrogens, N = number of nitrogens, and X = number of halogens.

Step 2: Identify the molecular formula provided in the problem. Extract the number of carbons (C), hydrogens (H), nitrogens (N), and halogens (X) from the formula.

Step 3: Substitute the values of C, H, N, and X into the IHD formula. Ensure that you follow the order of operations correctly: first calculate the numerator (2C + 2 - H + N - X), then divide by 2.

Step 4: Interpret the result of the IHD calculation. Each unit of IHD corresponds to one degree of unsaturation, which could be a ring, a double bond, or a triple bond. For example, an IHD of 1 could mean one double bond or one ring, while an IHD of 2 could mean two double bonds, one triple bond, or a combination of a ring and a double bond.

Step 5: If the problem includes a structure, verify the calculated IHD by analyzing the structure visually. Count the number of rings, double bonds, and triple bonds to confirm that the calculated IHD matches the structural features of the molecule.

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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 used in organic chemistry to determine the degree of unsaturation in a molecule. It indicates the number of rings and/or multiple bonds present in a compound. 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

A molecular formula represents the number and types of atoms in a molecule, providing essential information about its composition. It is expressed as CxHy, where x and y denote the number of carbon and hydrogen atoms, respectively. Understanding the molecular formula is crucial for calculating the IHD, as it directly influences the values of C, H, N, and X in the IHD formula.

Unsaturation

Unsaturation refers to the presence of double or triple bonds between carbon atoms or the presence of rings in a molecule. Each degree of unsaturation corresponds to a loss of hydrogen atoms compared to a saturated hydrocarbon. Recognizing unsaturation is vital for interpreting the IHD, as it helps predict the reactivity and stability of organic compounds.

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