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

26. Amines

Amine Alkylation

Organic Chemistry

26. Amines

Amine Alkylation

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4:55 minutes

Problem 6c

Textbook Question

Rank each set of compounds in order of increasing basicity.
(c) aniline, pyrrole, pyridine, piperidine

Verified step by step guidance

Step 1: Understand the concept of basicity. Basicity refers to the ability of a compound to donate a lone pair of electrons to accept a proton (H⁺). Factors affecting basicity include the availability of the lone pair, resonance effects, inductive effects, and hybridization of the nitrogen atom.

Step 2: Analyze aniline (structure i). Aniline has a nitrogen atom directly attached to a benzene ring. The lone pair on the nitrogen is partially delocalized into the aromatic ring via resonance, reducing its availability to accept a proton. This decreases its basicity.

Step 3: Analyze pyrrole (structure ii). Pyrrole is a five-membered aromatic ring with a nitrogen atom. The lone pair on the nitrogen is fully involved in maintaining the aromaticity of the ring, making it unavailable for protonation. Pyrrole is less basic than aniline.

Step 4: Analyze pyridine (structure iii). Pyridine is a six-membered aromatic ring with a nitrogen atom. The lone pair on the nitrogen is not involved in the aromaticity of the ring and is available for protonation. This makes pyridine more basic than both aniline and pyrrole.

Step 5: Analyze piperidine (structure iv). Piperidine is a six-membered saturated ring with a nitrogen atom. The nitrogen is sp³ hybridized, and its lone pair is fully available for protonation without any resonance effects. This makes piperidine the most basic compound in the set.

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Key Concepts

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

Basicity in Organic Chemistry

Basicity refers to the ability of a compound to accept protons (H+) in a chemical reaction. In organic chemistry, basicity is influenced by the availability of a lone pair of electrons on a nitrogen atom, which can bond with protons. The strength of a base is often compared using pKa values, where lower pKa indicates a stronger base.

Aromaticity and Electron Delocalization

Aromatic compounds, such as pyridine and pyrrole, exhibit unique stability due to electron delocalization within a cyclic structure. This delocalization can affect basicity; for instance, in pyrrole, the nitrogen's lone pair is involved in the aromatic system, making it less available for protonation compared to pyridine, where the lone pair is more accessible.

Steric and Electronic Effects

Steric effects arise from the spatial arrangement of atoms in a molecule, which can hinder or facilitate interactions with protons. Electronic effects, such as inductive and resonance effects, influence the electron density around the nitrogen atom. For example, piperidine, a saturated nitrogen-containing compound, is more basic than aniline due to less steric hindrance and greater availability of the lone pair for protonation.

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