Write a balanced chemical equation for the overall reaction represented below.

Pt | Fe2+, Fe3+ || Cl- | AgCl | Ag

Fe^{+2} \rightleftharpoons Fe^{+3} + e^-

Ag^+ + e^- \rightleftharpoons Ag

Add those together in a manner so as to balance charge (and, therefore eliminate e-).

Chloride does nothing except precipitate AgCl.

Ag^+ + Cl^{-} \rightarrow AgCl(s)

The Pt might be a catalyst, but quite honestly, I don't see it doing anything in this reaction.

I won't have understand a thing about that question!!