Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

17. Amines

Functional Group Priorities

GOB Chemistry

17. Amines

Functional Group Priorities

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Problem 57

Textbook Question

Benzene and pyridine are both single-ring, aromatic compounds. Benzene is a neutral compound that is insoluble in water. Pyridine, with a similar molar mass, is basic and completely miscible with water. Explain these phenomena.

Verified step by step guidance

Benzene is a neutral, nonpolar compound because it consists of a symmetrical ring of carbon atoms with delocalized π-electrons. This lack of polarity makes it insoluble in water, as water is a polar solvent and follows the principle 'like dissolves like.'

Pyridine, on the other hand, is also an aromatic compound but contains a nitrogen atom in its ring structure. This nitrogen atom has a lone pair of electrons, which makes pyridine a basic compound capable of accepting protons (H⁺).

The nitrogen atom in pyridine introduces polarity to the molecule, making it more hydrophilic (water-attracting) compared to benzene. This polarity allows pyridine to form hydrogen bonds with water molecules.

The ability of pyridine to form hydrogen bonds and its polar nature make it completely miscible with water, meaning it can dissolve in water in all proportions.

In summary, the difference in solubility between benzene and pyridine arises from the presence of the nitrogen atom in pyridine, which imparts polarity and basicity, enabling interactions with water molecules, unlike the nonpolar benzene.

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Key Concepts

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

Aromatic Compounds

Aromatic compounds are cyclic structures that follow Huckel's rule, possessing a planar ring of atoms with delocalized pi electrons. This delocalization contributes to their stability and unique chemical properties. Both benzene and pyridine are aromatic, but their differing structures lead to distinct behaviors in terms of solubility and reactivity.

Polarity and Solubility

Polarity refers to the distribution of electrical charge over the atoms in a molecule. Benzene is a nonpolar molecule due to its symmetrical structure and lack of electronegative atoms, making it insoluble in water. In contrast, pyridine contains a nitrogen atom, which introduces polarity and allows it to interact favorably with water, resulting in its complete miscibility.

Basicity of Pyridine

Basicity is the ability of a compound to accept protons (H+ ions). Pyridine is basic because the nitrogen atom has a lone pair of electrons that can readily accept a proton, forming a positively charged pyridinium ion. This property contrasts with benzene, which lacks basic sites and does not exhibit proton-accepting behavior, contributing to their differing chemical reactivities.

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