$Mn^{2+} +2e- \rightarrow Mn;\, E^o = -1.18\,V$
$2(Mn^{3+} +e^- \rightarrow Mn^{2+} )\,;\,E^o=+1.51\,V$
તો $3Mn^{2+} \rightarrow Mn+ 2Mn^{3+}$ માટે $E^o$ કેટલો થશે ?
$Zn | Zn ^{2+}(0.1\, M ) \| Ag ^{+}(0.01 \,M )| Ag$
[આપેલ $: E_{Z n^{+2}/Z_{n}}^{0}=-0.76 \,V ; E _{A g^{+} / A_{ g }}^{0}=+0.80 \,V ; \frac{2.303 RT }{ F }=0.059$]
$Fe_{(aq)}^{3 + } + {e^ - } \to Fe_{(aq)}^{2 + }$ ; ${E^o} = 0.771{\mkern 1mu} \,volts;{\mkern 1mu} $
${\mkern 1mu} {I_{2(g)}} + 2{e^ - } \to 2I_{(aq)}^ - \,;{\mkern 1mu} $ ${E^o} = 0.536{\mkern 1mu} \,volts$
કોષ પક્રિયા $2Fe^{3+}_{(aq)} + 2l^{-}_{(aq)} \rightarrow 2Fe^{2+}_{(aq)} + I_{2(g)}$ માટે $E^o_{cell} = ….$