A standard silver-zinc button cell has an EMF of +1.56 V. The cell consists of two electrodes with the following half-equations:
positive electrode:
Ag2O(s)+H2O(l)+2e−→2Ag(s)+2OH−(aq) \text{Ag}_2\text{O}(\text{s}) + \text{H}_2\text{O}(\text{l}) + 2\text{e}^- \rightarrow 2\text{Ag}(\text{s}) + 2\text{OH}^-(\text{aq}) Ag2O(s)+H2O(l)+2e−→2Ag(s)+2OH−(aq)negative electrode:
Zn(OH)2(s)+2e−→Zn(s)+2OH−(aq)E⊖=−1.22 V \text{Zn(OH)}_2(\text{s}) + 2\text{e}^- \rightarrow \text{Zn}(\text{s}) + 2\text{OH}^-(\text{aq}) \quad E^\ominus = -1.22\text{ V} Zn(OH)2(s)+2e−→Zn(s)+2OH−(aq)E⊖=−1.22 VWhat is the standard electrode potential of the Ag2O/Ag\text{Ag}_2\text{O} / \text{Ag}Ag2O/Ag electrode?
−2.78 V-2.78\text{ V}−2.78 V
−0.34 V-0.34\text{ V}−0.34 V
+0.34 V+0.34\text{ V}+0.34 V
+2.78 V+2.78\text{ V}+2.78 V
