$\Lambda_{C H_{3} C O O H}^{o}=\left(\Lambda_{C H_{3} C O O N a}^{o}+\Lambda_{H C l}^{o}\right)-\left(\Lambda_{N a C l}^{o}\right)$
Hence $\Lambda_{N a C l}^{\circ}$ is required.
$Pt|{H_2}_{\left( {1{\mkern 1mu} atm} \right)}|0.1{\mkern 1mu} M{\mkern 1mu} HCl||{\mkern 1mu} {\mkern 1mu} 0.1{\mkern 1mu} M\,C{H_3}COOH|{H_2}_{\left( {1{\mkern 1mu} atm} \right)}|Pt$
$[\Lambda_{\mathrm{H}^{+}}^{\circ}=350 \,\mathrm{~S}\, \mathrm{~cm}^{2}\, \mathrm{~mol}^{-1},\Lambda_{\mathrm{CH}_{3} \mathrm{COO}^{-}}^{\circ}=50\, \mathrm{~S}\, \mathrm{~cm}^{2}\, \mathrm{~mol}^{-1}]$
$(i)$ $A + e \rightarrow A^{-} ; E^o= -0.24 V$
$(ii)$ $B^{-} + e \rightarrow B^{2-}; E^o = + 1.25 V$
$(iii)$ $C^{-} + 2e \rightarrow C^{3-}; E^o = -1.25 V $
$(iv)$ $D + 2e \rightarrow D^{2-}; E^o = + 0.68 V$
$Fe_{(aq)}^{3 + } + {e^ - } \to Fe_{(aq)}^{2 + }$ ; ${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 $E^o_{cell} = ….$