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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3:21 minutes

Problem 6b

Textbook Question

Rank each set of compounds in order of increasing basicity.
(b) aniline, p-methylaniline, p-nitroaniline

Verified step by step guidance

Step 1: Understand the concept of basicity in organic chemistry. Basicity refers to the ability of a compound to donate a pair of electrons to accept a proton (H⁺). In aromatic amines like aniline and its derivatives, the electron density on the nitrogen atom determines the basicity.

Step 2: Analyze the substituents on the benzene ring for each compound. Substituents can either donate or withdraw electron density through resonance or inductive effects, which affects the electron density on the nitrogen atom. (i) Aniline has no substituents, (ii) p-methylaniline has a methyl group, and (iii) p-nitroaniline has a nitro group.

Step 3: Evaluate the effects of the substituents. The methyl group in p-methylaniline is an electron-donating group via hyperconjugation and inductive effects, increasing the electron density on the nitrogen atom and making it more basic. The nitro group in p-nitroaniline is an electron-withdrawing group via resonance and inductive effects, decreasing the electron density on the nitrogen atom and making it less basic.

Step 4: Rank the compounds based on their basicity. The compound with the highest electron density on the nitrogen atom will be the most basic, and the compound with the lowest electron density will be the least basic. Therefore, p-methylaniline will be the most basic, followed by aniline, and p-nitroaniline will be the least basic.

Step 5: Final ranking in order of increasing basicity: p-nitroaniline < aniline < p-methylaniline.

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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 often influenced by the presence of electron-donating or electron-withdrawing groups attached to a nitrogen atom in amines. The more readily a compound can donate its lone pair of electrons to bond with a proton, the stronger its basicity.

Electron-Donating and Electron-Withdrawing Groups

Electron-donating groups (EDGs) such as alkyl groups increase the electron density on the nitrogen atom, enhancing basicity. Conversely, electron-withdrawing groups (EWGs) like nitro groups decrease electron density, making the nitrogen less basic. Understanding the effects of these groups is crucial for predicting the basicity of substituted amines.

Resonance Effects

Resonance refers to the delocalization of electrons within a molecule, which can stabilize or destabilize certain functional groups. In the case of aniline derivatives, resonance can affect the availability of the nitrogen's lone pair for protonation. For example, in p-nitroaniline, the nitro group withdraws electron density through resonance, reducing the basicity compared to aniline and p-methylaniline.

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