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

Previous problemNext problem

Problem 3c

Textbook Question

Calculate the index of hydrogen deficiency for the following molecules.
(c)

Verified step by step guidance

Step 1: Understand the concept of Index of Hydrogen Deficiency (IHD). IHD is a measure of the number of degrees of unsaturation in a molecule. Each degree of unsaturation corresponds to either a double bond, a ring, or a triple bond. The formula for IHD is: IHD = (2C + 2 - H + N - 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.

Step 2: Count the number of carbons (C) in the molecule. From the structure provided, count all the carbon atoms in the molecule, including those in the rings and chains.

Step 3: Count the number of hydrogens (H) in the molecule. This includes all hydrogens attached to the carbons in the structure. Note that implicit hydrogens are not shown in the skeletal structure but must be accounted for based on the valency of carbon.

Step 4: Identify the degrees of unsaturation in the molecule. Look for double bonds, triple bonds, and rings in the structure. Each double bond and ring contributes 1 degree of unsaturation, while each triple bond contributes 2 degrees of unsaturation.

Step 5: Plug the values into the IHD formula. Use the counts of carbons, hydrogens, and any other relevant atoms (if applicable) to calculate the IHD. Simplify the formula to determine the number of degrees of unsaturation in the molecule.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Play a video:

Was this helpful?

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. 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

The molecular formula of a compound provides the exact number of each type of atom in a molecule. It is essential for calculating the IHD, as it directly influences the values of C, H, N, and X in the IHD formula. Understanding how to derive the molecular formula from a structural representation is crucial for accurately determining the IHD.

Unsaturation

Unsaturation refers to the presence of double or triple bonds in a molecule, as well as rings. 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.

Watch next

Master The difference between saturated and unsaturated molecules. with a bite sized video explanation from Johnny

Start learning

Related Videos

Related Practice

Textbook Question

Given the molecular formula, calculate the index of hydrogen deficiency.

(a) C₆H₁₄O

Textbook Question

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

(f) C₆H₈O₂

Textbook Question

What is the index of hydrogen deficiency for each of the following molecular formulas?

(e) C₆H₁₂O₂

Textbook Question

What is the index of hydrogen deficiency for each of the following molecular formulas?

(b) C₁₂H₁₁NO₃

Textbook Question

For each molecular formula, represent all constitutional isomers using line-angle drawings.

Textbook Question

Determine the degree of unsaturation for hydrocarbons with the following molecular formulas:

c. C₁₂H₂₀

d. C₄₀H₅₆

Textbook Question

Several studies have shown that β-carotene, a precursor of vitamin A, may play a role in preventing cancer. β-Carotene has a molecular formula of C₄₀H₅₆, and it contains two rings and no triple bonds. How many double bonds does it have?

Textbook Question

Give five examples of structures with this formula (C₆H₁₂). At least one should contain a ring, and at least one should contain a double bond.

Hint: If you prefer to use a formula, elements of unsaturation = 1/2(2C + 2 - H)

C = number of carbons

H = number of hydrogens

Show more practices