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

6:55 minutes

Problem 45c

Textbook Question

The following compounds can all react as acids.

c. Rank the original compounds in order, from strongest acid to weakest acid.

Verified step by step guidance

Identify the functional groups in each compound: CH3COOH, CF3COOH, CF3CH2COOH, and CH3CH2OH. The first three are carboxylic acids, and the last one is an alcohol.

Understand that the acidity of a compound is influenced by the stability of its conjugate base. A more stable conjugate base corresponds to a stronger acid.

Consider the effect of electronegative substituents on acidity. Electronegative groups, like CF3, can stabilize the conjugate base through inductive effects, increasing acidity.

Rank the compounds based on the presence and position of electronegative groups: CF3COOH has the strongest electron-withdrawing group directly attached to the carboxyl group, making it the strongest acid.

Compare the remaining compounds: CF3CH2COOH is next due to the electron-withdrawing effect of CF3, followed by CH3COOH, and finally CH3CH2OH, which is the weakest acid due to the lack of electron-withdrawing groups and being an alcohol.

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.

Acidity and pKa

Acidity refers to the ability of a compound to donate a proton (H+) in a chemical reaction. The strength of an acid is often measured by its pKa value; lower pKa values indicate stronger acids. Understanding the relationship between structure and acidity is crucial for ranking acids, as factors like electronegativity and resonance can significantly influence a compound's ability to stabilize the negative charge after deprotonation.

Inductive Effect

The inductive effect describes how the presence of electronegative atoms or groups in a molecule can influence the acidity of nearby protons. Electronegative atoms, such as fluorine, can withdraw electron density through sigma bonds, stabilizing the negative charge on the conjugate base formed after deprotonation. This effect is particularly important in determining the relative acidity of compounds with different substituents.

Resonance Stabilization

Resonance stabilization occurs when a molecule can distribute its electron density across multiple structures, leading to increased stability of the conjugate base. In the context of acidity, compounds that can delocalize the negative charge through resonance after losing a proton will generally be stronger acids. Recognizing which structures can participate in resonance is essential for ranking the acidity of the given compounds.

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

The following compound can become protonated on any of the three nitrogen atoms. One of these nitrogens is much more basic than the others, however.

b. Determine which nitrogen atom is the most basic.

Textbook Question

Choose the more basic member of each pair of isomers, and show why the base you chose is more basic.

(a)

(b)

Textbook Question

The following compounds are listed in increasing order of acidity. In each case, the most acidic proton is shown in red.

b. Explain why X is a stronger acid than W.

c. Explain why Y is a stronger acid than X.

d. Explain why Z is a stronger acid than Y.

Textbook Question

Choose the more acidic member of each pair of isomers, and show why the acid you chose is more acidic.

(a)

(b)

(c)

Textbook Question

Consider the type of orbitals involved, and rank the following nitrogen compounds in order of decreasing basicity. 2. Rank the conjugate acids in order of increasing acidity. (Hint: These two orders should be the same!)

Textbook Question

Consider each pair of bases, and explain which one is more basic. Draw their conjugate acids, and show which one is a stronger acid.

(a)

(b)

Textbook Question

Write equations for the following acid–base reactions. Label the conjugate acids and bases, and show any inductive stabilization. Predict whether the equilibrium favors the reactants or products. Try to do this without using a table of pKa values, but if you need a hint, you can consult Appendix 4.

a. CH₃CH₂OH + CH₃NH⁻

b. F₃CCOONa + Br₃C—COOH

c. CH₃OH + H₂SO₄

Textbook Question

Ethanol, methylamine, and acetic acid are all amphoteric, reacting as either acids or bases depending on the conditions.

b. Rank ethanol, methylamine, and acetic acid in decreasing order of basicity. In each case, show the equation for the reaction with a generic acid (HA) to give the conjugate acid.

Show more practices

Download the Mobile app

Privacy

Do not sell my personal information

Accessibility

Patent notice

Sitemap

The following compounds can all react as acids.c. Rank the original compounds in order, from strongest acid to weakest acid.

Key Concepts

Acidity and pKa

Inductive Effect

Resonance Stabilization

Watch next

The following compounds can all react as acids.

c. Rank the original compounds in order, from strongest acid to weakest acid.