$(i)$ $Zn| Zn^{2+} {(1\,M)}|| Cu^{2+}{(0.1\,M)}| Cu$
$(ii)$ $Zn| Zn^{2+} {(1\,M)}|| Cu^{2+}(1\,M) |Cu $
$(iii)$ $Zn| Zn^{2+} {(0.1\,M)}|| Cu^{2+}{(1\,M)}| Cu$
જેમ \(log [Zn^{2+}]/[Cu^{2+}]\) નું મૂલ્ય જેમ વધુ તેમ \(E\) નું મૂલ્ય ઓછું.
\({\text{(i)}}\,\,{\text{log }}\left[ {\frac{{{\text{Z}}{{\text{n}}^{{\text{2 + }}}}}}{{{\text{C}}{{\text{u}}^{{\text{2 + }}}}}}} \right] = 10;\,\,\,\,\,\,(ii)\,\,{\text{log }}\left[ {\frac{{{\text{Z}}{{\text{n}}^{{\text{2 + }}}}}}{{{\text{C}}{{\text{u}}^{{\text{2 + }}}}}}} \right]\)\( = 1;\,\,\)
\(\,(iii)\,\,{\text{log }}\left[ {\frac{{{\text{Z}}{{\text{n}}^{{\text{2 + }}}}}}{{{\text{C}}{{\text{u}}^{{\text{2 + }}}}}}} \right] = 0.1\,\,\,\,\,\,\,\therefore \,\,\,\,{E_3} > {E_2} > {E_1}\)
$(i)\, A3^-\rightarrow A^{2-} + e; E° = 1.5 \,V$
$(ii) \,B^{+}+ e \rightarrow B; E° = 0.5 \,V$
$(iii)\, C^{2+} + e \rightarrow C^{+}; E°= 0.5\, V$
$(iv)\, D \rightarrow D^{2+}+ 2e; E° = -1.15\, V$
$Pt|{H_2}_{\left( {1{\mkern 1mu} atm} \right)}|0.1{\mkern 1mu} M{\mkern 1mu} HCl||{\mkern 1mu} {\mkern 1mu} 0.1{\mkern 1mu} M\,C{H_3}COOH|{H_2}_{\left( {1{\mkern 1mu} atm} \right)}|Pt$