• # question_answer 74) On the basis of standard electrode potential values, suggest which of the following reactions would take place?(Consult the book for ${{E}^{O-}}$ value).(i) $Cu+Z{{n}^{2+}}\to C{{u}^{2+}}+Zn$(ii) $Mg+F{{e}^{2+}}\to M{{g}^{2+}}+Fe$(iii) $B{{r}_{2}}+2C{{l}^{-}}\to C{{l}_{2}}+2B{{r}^{-}}$(iv)$Fe+C{{d}^{2+}}\to Cd+F{{e}^{2+}}$

(i) $Cu+Z{{n}^{2+}}\to C{{u}^{2+}}+Zn$ $E_{\operatorname{Re}dox\,process}^{{}^\circ }=E_{\operatorname{Re}duced\,species}^{{}^\circ }-E_{Oxidised\,species}^{{}^\circ }$                 $=E_{Z{{n}^{2+}}/Zn}^{{}^\circ }-E_{C{{u}^{2+}}/Cu}^{{}^\circ }$                 $=(-0.76)-(+0.34)=-1.10V$ Negative value shows that the redox process is not feasible. (ii) $Mg+F{{e}^{2+}}\to M{{g}^{2+}}+Fe$ $E_{\operatorname{Re}dox\,process}^{{}^\circ }=E_{\operatorname{Re}duced\,species}^{{}^\circ }-E_{Oxidised\,species}^{{}^\circ }$                       $=E_{F{{e}^{2+}}/Fe}^{{}^\circ }-E_{M{{g}^{2+}}/Mg}^{{}^\circ }$                 $=-0.44-(-2.36)=+1.92V$ Positive value shows that the redox process is feasible. (iii)  $B{{r}_{2}}+2C{{l}^{-}}\to C{{l}_{2}}+2B{{r}^{-}}$                 $E_{\operatorname{Re}dox\,process}^{{}^\circ }=E_{\operatorname{Re}duced\,species}^{{}^\circ }-E_{Oxidised\,species}^{{}^\circ }$                                                 $=E_{B{{r}_{2}}/Br}^{{}^\circ }-E_{C{{l}_{2}}/C{{l}^{-}}}^{{}^\circ }$                                                 $=+1.09-1.36=-ve$ Negative value shows that the redox process is not feasible. (iv)   $Fe+C{{d}^{2+}}\to Cd+F{{e}^{2+}}$                        $E_{\operatorname{Re}dox\,process}^{{}^\circ }=E_{\operatorname{Re}duced\,species}^{{}^\circ }-E_{Oxidised\,species}^{{}^\circ }$                                 $=E_{C{{d}^{2}}/Cd}^{{}^\circ }-E_{F{{e}^{2+}}Fe}^{{}^\circ }$                                 $=(-0.40)-(-0.44)=+0.04V$ Positive value shows that the redox process is feasible.