If the cell potential of the cell at $298 \ K$ is $2.36 \ V$,write the cell reaction and calculate the standard electrode potential of the $Mg^{2+} \mid Mg$ half-cell.
$Mg_{(s)} \mid Mg^{2+}_{(1 \ M)} \parallel H^{+}_{(1 \ M)} \mid H_{2(g)} (1 \ bar) \mid Pt_{(s)}$

• A
  Anode: $Mg \rightarrow Mg^{2+} + 2e^-$,Cathode: $2H^+ + 2e^- \rightarrow H_2$,$E^\circ_{Mg^{2+}/Mg} = -2.36 \ V$
• B
  Anode: $Mg \rightarrow Mg^{2+} + 2e^-$,Cathode: $2H^+ + 2e^- \rightarrow H_2$,$E^\circ_{Mg^{2+}/Mg} = +2.36 \ V$
• C
  Anode: $Mg^{2+} + 2e^- \rightarrow Mg$,Cathode: $H_2 \rightarrow 2H^+ + 2e^-$,$E^\circ_{Mg^{2+}/Mg} = -2.36 \ V$
• D
  Anode: $Mg \rightarrow Mg^{2+} + 2e^-$,Cathode: $2H^+ + 2e^- \rightarrow H_2$,$E^\circ_{Mg^{2+}/Mg} = -1.18 \ V$