Question

Reduction Reaction E0 (V)
Cadmium (Cd) Cd2+ + 2e– → Cd -0.40
Silver (Ag) Ag+ + e– → Ag +0.80


If the standard cell potential of a cadmium-silver cell is 1.20 V and the reduction potential of Cd is –0.40 V, what is the oxidation potential of Ag?

-1.60
+1.60
-0.80
+0.80

Answer 1

I'm not sure why all of that information is given. I wonder if y ou've looked up the reduction of Ag. You can take the short cut. If the reduction potential of Ag^+ + e --> Ag is 0.80 then the oxidation potential is the reverse reaction written as an oxidation and change the sign to -0.80. However, if the reduction potential of the Ag^+/Ago is NOT given then the problem is done this way.
Cd ==> Cd^2+ + 2e .........Eox = + 0.40 volts
2Ag^+ + 2e --> 2Ag ..........Ered = ? volts
--------------------------------------------------
Cd + 2Ag^+ ==> 2Ag + Cd^2+ Ecell = 1.20 volts
So then you ask yourself if Eox + Ered = 1.20 v and Eox = 0.40, then
0.40 + Ered = 1.20 v and you solve for Ered.

Answer 2

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