Calculate the standard potential for this cell at 25 °C

Question

A galvanic (voltaic) cell consists of an electrode composed of zinc in a 1.0 M1.0 M zinc ion solution and another electrode composed of silver in a 1.0 M1.0 M silver ion solution, connected by a salt bridge. Calculate the standard potential for this cell at 25 °C. Refer to the list of standard reduction potentials.

Answer 1

From the table of standard reduction potentials:

Zn²⁺ + 2e- ==> Zn Eº = -0.76 V

Ag⁺ + e- ==> Ag Eº = +0.80 V

So Ag + will be reduced and Zn will be oxidized and the half reactions will be:

2Ag⁺_(aq) +2e- ==> 2Ag(s) ... +0.80 (CATHODE)

Zn(s) ==> Zn²⁺(aq) ... -0.76 (ANODE)

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2Ag⁺(aq) + Zn(s) ==> 2Ag(s) + Zn²⁺(aq) .. overall reaction for the galvanic cell

Eº_cell = cathode - anode = 0.80 - (-0.76) = 0.80 + 0.76

Eº_cell = 1.56 V