Giải :
(\eqalign{& a.{\rm E}_{Pin\left( {Fe - Pb} \right)}^0 = {\rm E}_{P{b^{2 + }}/Pb}^0 - {\rm E}_{F{e^{2 + }}/Fe}^0 = - 0,13 - ( - 0,44) = + 0,31V. \cr & b.{\rm E}_{Pin\left( {Fe - Ag} \right)}^0 = {\rm E}_{A{g^ + }/Ag}^0 - {\rm E}_{F{e^{2 + }}/Fe}^0 = + 0,80 - ( - 0,44) = + 1,24V. \cr& c.{\rm E}_{Pin\left( {Pb - Ag} \right)}^0 = {\rm E}_{A{g^ + }/Ag}^0 - {\rm E}_{P{b^{2 + }}/Pb}^0 = + 0,80 - ( - 0,13) = + 0,93V. \cr} \)