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A button cell used in watches functions as following: $Zn(s) + Ag_2O(s) + H_2O(l) \rightleftharpoons 2Ag(s) + Zn^{2+}(aq) + 2OH^-(aq)$. If half cell potentials are $Zn^{2+}(aq) + 2e^- \rightarrow Zn(s)$; $E^\circ = -0.76$ V and $Ag_2O(s) + H_2O(l) + 2e^- \rightarrow 2Ag(s) + 2OH^-(aq)$; $E^\circ = 0.34$ V, the cell potential will be:
A
1.34 V
B
1.10 V
C
0.42 V
D
0.84 V
Detailed Solution
$E^\circ_{cell} = (E^\circ_{R.P.})_{cathode} - (E^\circ_{R.P.})_{anode}$
$E^\circ_{cell} = 0.34 - (-0.76) = 1.10$ V
$E^\circ_{cell} = 0.34 - (-0.76) = 1.10$ V