Question

An electrochemical cell of notation Pd | Pd²⁺ || Cu²⁺ | Cu has E° = -0.65 V. If we know that the standard reduction potential of Cu²⁺/Cu is E° = 0.34 V, what is the standard reduction potential for Pd²⁺/Pd?

Answer 1

Pd | Pd²⁺ || Cu²⁺ | Cu
.......Pd(s) ==> Pd^2+(aq) + 2e..........Eo = ?
......Cu^2+(aq) + 2e ==> Cu(s)............Eo = 0.34
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.....Pd(s) + Cu^2+(aq) --> Pd^2+(aq) + Cu(s) Ecell = -0.65
Ecell = ? + 0.34
-0.65 = ? + 0.34
? = -0.65 - 0.34 = -0.99
So Pd(s) ==> Pd^2+(aq) + 2e has Eo value of -0.99; however this is written as an oxidation. The problems wants the reduction potential; therefore, the redn pot is +0.99