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

3. Acids and Bases

Ranking Acidity

Organic Chemistry

3. Acids and Bases

Ranking Acidity

Previous problemNext problem

2:26 minutes

Problem 49

Textbook Question

Rank the following amines in order of their basicity (strongest base = 1 ; weakest base = 6).

Verified step by step guidance

Identify the amines in the given list and note their structural features, such as alkyl groups, aromatic rings, or electron-withdrawing/donating substituents. These features influence the basicity of the amine.

Recall that the basicity of an amine is determined by the availability of the lone pair of electrons on the nitrogen atom. Electron-donating groups increase basicity by making the lone pair more available, while electron-withdrawing groups decrease basicity by delocalizing or withdrawing electron density.

Consider the effect of resonance. For example, if the nitrogen's lone pair is delocalized into an aromatic ring (as in aniline derivatives), the basicity decreases because the lone pair is less available for protonation.

Evaluate the inductive effects of substituents. Alkyl groups are electron-donating via the inductive effect, which increases basicity, while electronegative atoms or groups (e.g., halogens, nitro groups) are electron-withdrawing and decrease basicity.

Rank the amines based on the combined effects of resonance, inductive effects, and steric hindrance, starting with the strongest base (most available lone pair) as 1 and ending with the weakest base (least available lone pair) as 6.

Verified video answer for a similar problem:

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

Video duration:

Play a video:

Was this helpful?

Key Concepts

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

Basicity of Amines

Basicity in amines refers to their ability to accept protons (H+) from acids. This property is influenced by the availability of the lone pair of electrons on the nitrogen atom, which can bond with protons. The more readily an amine can donate its lone pair, the stronger its basicity.

Inductive Effect

The inductive effect describes how electron-withdrawing or electron-donating groups attached to the amine can influence its basicity. Electron-donating groups (like alkyl groups) increase basicity by stabilizing the positive charge on the nitrogen when it accepts a proton, while electron-withdrawing groups decrease basicity by destabilizing this charge.

Steric Hindrance

Steric hindrance refers to the spatial arrangement of atoms around the nitrogen in an amine, which can affect its ability to interact with protons. Bulky groups near the nitrogen can hinder access to the lone pair, reducing basicity. Thus, the size and arrangement of substituents play a crucial role in determining the overall basicity of amines.

Watch next

Master Why we need factors affecting acidity and when to use them. with a bite sized video explanation from Johnny

Start learning

Related Videos

Related Practice

Textbook Question

Explain the relative acidities.

CH₂═CHCH₂OH, CH₃CH₂CH₂OH, HC≡CCH₂OH

Textbook Question

Using the table of pK_a values given in [Appendix I] , answer the following:

d. Which is more electronegative: an sp³ oxygen or an sp² oxygen?

e. Which compounds demonstrate that the relative electronegativities of a hybridized nitrogen atom are sp > sp² > sp³?

Textbook Question

Imidazole has two potentially basic sites (a and b). Of the two, where would you expect a proton to add preferentially?

Textbook Question

Rationalize the rather large difference in pK_a values for the two carboxylic acids shown.

Textbook Question

Which acid in each pair would you expect to more readily donate a proton to a basic compound?

(b)

Textbook Question

Using qualitative reasoning for the acid–base reactions shown,

(i) which is stronger, the acid or the conjugate acid?

(ii) Which side of the reaction is favored?

(iii) Would you expect a K_eq greater than, equal to, or less than 1?

(a)

Textbook Question

Using qualitative reasoning for the acid–base reactions shown,

(i) which is stronger, the base or the conjugate base?

(ii) Which side of the reaction is favored?

(iii) Would you expect a K_eq greater than or less than 1?

(a)

Textbook Question

Identify the most stable conjugate base in each pair. Tell which structural features you analyzed and why you weighted them as you did in picking one answer.

(c)

Show more practices

Download the Mobile app

Privacy

Do not sell my personal information

Accessibility

Patent notice

Sitemap