As a teacher of physical chemistry, I noticed that students, even in advanced classes, have difficulties in understanding the basics of redox chemistry. In this Section 6, I attempted to discuss some applications of the Nernst equation in electrochemical systems, including energy (consumption or generation), corrosion, redox titration, as well as the study of solubility, precipitation, and complexation processes. To further clarify the discussed concepts, numerous questions and problems with detailed answers are provided. Most of these questions are formulated by students like you. I believe that this Section 6 would greatly help students with levels varying from high school to advanced university classes.