$E^oFe^{3+}_{(aq)} + e^{-} \rightarrow Fe^{2+}_{(aq)}$ કેટલા ............ $\mathrm{V}$ થાય?
$Fe^{3+}\,\,_{(aq)} + 3e^{-} \rightarrow Fe_{(s)}$ ; $E^o = -0.036 \,volt; $
$Fe^{2+}_{(aq)} + 2e^{-} \rightarrow Fe_{(s)}$ ; $E^o = -0.440 \,volt$
$Fe\, \to \,F{e^{ + 2}}\, + \,2{e^ - }$ $E_2^o\,= \,- \,0.044\,volt$ , ${n_2}\, = \,2$
$E_3^ o \, = \,\frac{{-{n_1}E_1^ o \, + \,{n_2}E_2^o }}{{{n_3}}}$ $=\,\frac{{-3\,\times \,\,(0.036)\,\, + \,2\,\times \,\,0.44}}{1}$
$ =0.772\,volt$
$2Fe(s)\, + \,{O_2}\,(g)\, + \,4{H^ + }(aq)\, \to \,2F{e^{2 + }}(aq) + 2{H_2}O(l)\,;$ $E^o =1.67\,V$
$[Fe^{2+}] = 10^{-3}\, M$, $p(O_2) = 0.1\,atm$ અને $pH = 3$, $25\,^oC$ તાપમાને સેલ પોટેન્શિયલ .............. $\mathrm{V}$