Lecture 06 - Bronsted Acidity and the Generality of Nucleophilic Substitution. The coincidentally substantial extent of ionic dissociation of water provides an example of Bronsted acidity,
or nucleophilic substitution at hydrogen. Relative pKa values are insensitive enough to solvent that they provide insight on the role of energy-match, overlap, and resonance in ionic dissociation.
The titration of alanine in water illustrates the experimental determination of pKa values and the phenomenon of buffering. The limited pKa scale in water can be extended dramatically by titration
in other solvents, providing one of the best ways to measure many "effects" in organic chemistry. A wide range of important organic reactions discovered in the 19th century and many biochemical reactions
can be understood under the rubric of nucleophilic substitution.
(from oyc.yale.edu)
Lecture 06 - Bronsted Acidity and the Generality of Nucleophilic Substitution
Time
Lecture Chapters
[00:00:00]
1. Solvent Influence on Ionic Dissociation
[00:04:45]
2. Bronsted Acidity as Nucleophilic Substitution at Hydrogen
[00:11:09]
3. Understanding Relative pKa in Terms of Energy Match and Overlap
[00:21:18]
4. Measuring the pKa Values of Alanine
[00:29:09]
5. Factors that Influence pKa over an Expanded Range