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

2. Molecular Representations

How To Determine Solubility

Organic Chemistry

2. Molecular Representations

How To Determine Solubility

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2:58 minutes

Problem 9a

Textbook Question

Rank the following molecules from least water soluble to most water soluble. Explain your reasoning.
(a) H₃C ― OH

Verified step by step guidance

Step 1: Begin by identifying the functional group present in the molecule H₃C ― OH. This molecule contains a hydroxyl (-OH) group, which is polar and capable of forming hydrogen bonds with water molecules.

Step 2: Recall that water solubility is influenced by the ability of a molecule to interact with water through hydrogen bonding or dipole-dipole interactions. Molecules with polar functional groups, such as -OH, tend to be more water-soluble than nonpolar molecules.

Step 3: Consider the size of the molecule and the presence of nonpolar regions. In H₃C ― OH, the methyl group (H₃C-) is nonpolar, but the hydroxyl group dominates the solubility behavior due to its strong polarity and hydrogen bonding capability.

Step 4: Compare this molecule to other molecules in the problem (if provided). Rank them based on the number and type of polar functional groups, the size of the nonpolar regions, and their ability to form hydrogen bonds with water.

Step 5: Conclude that H₃C ― OH is likely to be moderately water-soluble due to the presence of the hydroxyl group, which enhances its interaction with water despite the small nonpolar methyl group.

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Key Concepts

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

Polarity

Polarity refers to the distribution of electrical charge over the atoms in a molecule. Molecules with polar bonds, such as those containing hydroxyl (–OH) groups, tend to interact favorably with water, a polar solvent. Understanding the polarity of the functional groups in the molecules is essential for predicting their solubility in water.

Hydrogen Bonding

Hydrogen bonding occurs when a hydrogen atom covalently bonded to a highly electronegative atom, like oxygen, interacts with another electronegative atom. This type of bonding significantly increases the solubility of molecules in water, as it allows for strong interactions between the solute and solvent. Recognizing the presence and strength of hydrogen bonds in the molecules is crucial for ranking their solubility.

Molecular Size and Structure

The size and structure of a molecule influence its solubility in water. Larger, more complex molecules may have hydrophobic regions that hinder solubility, while smaller, simpler molecules with polar functional groups are generally more soluble. Analyzing the molecular structure helps in understanding how these factors contribute to the overall solubility in water.

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Related Practice

Textbook Question

Predict which member of each pair is more soluble in water. Explain your prediction.

(e)

(f)

Textbook Question

Predict which member of each pair is more soluble in water. Explain your prediction.

(c)

(d)

Textbook Question

Methoxychlor is an insecticide that was intended to take DDT’s place because it is not as soluble in fatty tissues and is more readily biodegradable. It, too, can accumulate in the environment, however, so its use was also banned—in 2002 in the European Union and in 2003 in the United States. Why is methoxychlor less soluble in fatty tissues than DDT?

Textbook Question

In which solvent would cyclohexane have the lowest solubility: 1-pentanol, diethyl ether, ethanol, or hexane?

Textbook Question

Predict which member of each group is most soluble in water, and explain the reasons for your predictions.

b. chlorocyclohexane, cyclohexanol, or cyclohexane-1,2-diol

Textbook Question

In each pair,

(i) choose the compound that is most soluble in water.

(ii) Within each pair, which is most soluble in nonpolar solvents?

(b)

Textbook Question

In each pair,