Question #44318

A standard galvanic cell is constructed at 298 K: Anode: $\ce{Pt | Sn^{2+}(1 M), Sn^{4+}(1 M)}$ Cathode: $\ce{Pt | Tl^{+}(1 M), Tl^{3+}(1 M)}$

Given the standard reduction potentials and constants at 298 K: $E^\circ_{\ce{Sn^{4+}/Sn^{2+}}} = +0.15\text{ V}$ $E^\circ_{\ce{Tl^{3+}/Tl^+}} = +1.26\text{ V}$ $E^\circ_{\ce{I_2/I^-}} = +0.54\text{ V}$ $K_{\text{sp}}(\ce{TlI}) = 10^{-8}$ $\frac{2.303RT}{F} = 0.06\text{ V}$

Excess solid $\ce{KI}$ is added to the cathode compartment until the concentration of free $\ce{I^-}$ reaches exactly $1\text{ M}$ at equilibrium. Solid $\ce{I_2}$ and $\ce{TlI}$ are observed to precipitate. (Assume $\ce{I_2}$ separates as a solid with unit activity, ignore $\ce{I_3^-}$ formation, and assume no volume change).

What is the new overall cell potential ($E_{\text{cell}}$) and the equilibrium concentration of $\ce{Tl^{3+}}$ in the cathode compartment?