Principle
The Nernst equation expresses how the electrical potential of an electrode in contact with a solution of ions depends upon the concentrations (more accurately, activities) of those ions. The equation may be experimentally verified using an electrochemical cell formed from an inert indictator electrode coupled with a convenient reference electrode. The potential of the indicator electrode, and hence the e.m.f. of the cell, is monitored as the ionic composition of the electrolyte solution is changed.
Benefits
- Relevant both for chemists and for physicists
- Essential introductory experiment for studying battery technology
Tasks
Using an Ag(S) I AgCl(S) l Cl- reference electrode, measure the potential of a platinum electrode in contant with solutions containing known concentration of the iron(II) and iron(lII) complex ions [Fe(CN)6]4 - and [Fe(CN)6]3-.
What you can learn about
- Electrode potentials and their concentration dependence
- Redox electrodes
- Electrochemical cells
Necessary accessories
- Analytical balance 120g/0.1mg
Software included. Computer not provided.