The correct option is C 0.521 V
The half-cell reactions are:
Cu2++2e−→Cu, Eo=0.337 V∴ΔG=−nFEo⇒ΔG=−2F×0.337 V
Cu2++2e−→Cu, ΔG=−2F×0.337 V...(i)
Cu+→Cu2++e−, Eo=−0.153 V⇒ΔG=1F×0.153 V
Cu+→Cu2++e− ,ΔG=1F×0.153 V...(ii)
By adding (i) and (ii), we get
Cu++e−→Cu ,ΔG=(−2F×0.337 V)+(1F×0.153 V)=−0.521F VAs, ΔG=−nFEo⇒−0.521F V=−FEo∴Eo=0.521 V