$M/M^+ | | N^+/N$
$E_{cell}^o\, = \,0.25\, - \,0.52\, = \, - \,0.27\,V$
$Fe \rightarrow Fe^{2+} + 2e^{-} , E^{o} = 0.44\,\, V , 2H^{+} + 2e^{-} + \frac{1}{2} O_2 \rightarrow H_2O_{(l)}, E_{o} = 1.23\, V$ તો આ પ્રક્રિયા માટે $\Delta G^{o} =....$ કિલોજૂલ / મોલ
$M{g^{2 + }} + 2{e^ - } \to Mg(s);\,\,E = - 2.37\,V$
$C{u^{2 + }} + 2{e^ - } \to Cu(s);\,\,\,E = + 0.33\,V$