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

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Problem 3b

Textbook Question

Which of the following indicated atoms would you expect to be most basic?
(b)

Verified step by step guidance

Step 1: Understand the concept of basicity. Basicity refers to the ability of a molecule or atom to donate a pair of electrons to accept a proton (H⁺). The more readily an atom can donate its lone pair of electrons, the more basic it is.

Step 2: Analyze the functional groups in the given molecules. The first molecule contains an -OH group (hydroxyl group), and the second molecule contains an -NH₂ group (amine group). Both groups have lone pairs of electrons on the oxygen and nitrogen atoms, respectively.

Step 3: Compare the electronegativity of the atoms involved. Oxygen is more electronegative than nitrogen, meaning it holds onto its electrons more tightly. This makes the lone pair on oxygen less available for donation compared to the lone pair on nitrogen.

Step 4: Consider the stability of the conjugate acid formed. When the -OH group donates its lone pair, it forms H₂O⁺, which is highly stable due to hydrogen bonding and resonance. In contrast, the conjugate acid formed by -NH₂ (NH₃⁺) is less stable, making -NH₂ more likely to donate its lone pair and thus more basic.

Step 5: Conclude that the nitrogen atom in the -NH₂ group is expected to be more basic than the oxygen atom in the -OH group due to its lower electronegativity and greater ability to donate its lone pair of electrons.

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Key Concepts

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

Basicity

Basicity refers to the ability of a substance to accept protons (H+) or donate electron pairs. In organic chemistry, basicity is influenced by the structure of the molecule, including the presence of electronegative atoms, resonance effects, and steric hindrance. A more basic atom typically has a lone pair of electrons that can readily bond with protons.

Electronegativity

Electronegativity is a measure of an atom's ability to attract and hold onto electrons. Atoms with high electronegativity, such as fluorine or oxygen, tend to be less basic because they hold onto their electrons tightly, making it harder for them to donate electron pairs. Understanding the electronegativity of the atoms in question is crucial for predicting their basicity.

Resonance Stabilization

Resonance stabilization occurs when a molecule can be represented by multiple valid Lewis structures, allowing for the delocalization of electrons. This delocalization can affect basicity; for instance, if a lone pair is involved in resonance, it may be less available to bond with protons, thus decreasing the basicity of that atom. Recognizing resonance structures is essential for evaluating the basicity of different atoms.

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