Question

Hi! Can anyone explain me how to calculate the activity of an oxidant/reductant? I have to calculate a silver/silver chloride electrode in physical chemistry.

Answer 1

\[E=E _{0}+\frac{ RT }{ zF }\ln \frac{ a _{ox} }{ a _{red} }\]
So I don't get how to derive a.

Answer 2

In your case, the redox couple is \(Ag^+/Ag\)
Half equation is \(Ag^++e^- \rightarrow Ag_{(s)}\)

Which leads to \(E=E _{0}+\Large\frac{ RT }{ zF }\ln \Large \frac{ [Ag^+]}{ 1 }\)

Answer 3

In the presence of chloride ions, \([Ag^+]=K_S/[Cl^-]\)
Bythe way \(z=1\) here.
After substituting [Ag+], you will get a workable equation.