Nernst Equation

Principle and tasks
The Nernst equation expresses how
the electrical potential of an electrode
in contact with a solution of ions depends
upon the activities of these 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, are monitored as the ionic
composition of the electrolyte solution
is changed.
Here a silver - silver chloride electrode
is used as reference electrode meas -
uring the potential of a platinum electrode
in contact with solutions containing
different concentrations of
iron(II) and iron(III) complex ions.
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 indicator 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.
Tasks
Using an Ag(s)
AgCl(s)
Cl- reference electrode, measure the
potential of a platinum electrode in contact with solutions containing
known concentrations of the iron(II) and iron(III) complex
ions [Fe(CN)6]4- and [Fe(CN)6]3-.