• # question_answer An iron rod is immersed in a solution containing $1.0\,M\,NiS{{O}_{4}}$ and $1.0\,M\,ZnS{{O}_{4}}$ . Predict giving reasons which of the following reactions is likely to proceed? (i) Fe reduces $Z{{n}^{2+}}$ ions, (ii) Iron reduces $N{{i}^{2+}}$ ions. Given: $E{{{}^\circ }_{Z{{n}^{2+}}/Zn}}=-0.76\,V,$$E{{{}^\circ }_{F{{e}^{2+}}/Fe}}=-0.44\,V$ $and\,\,\,{{E}^{{}^\circ }}_{N{{i}^{2+}}/Ni}=-0.25V$

(i) Since $E{}^\circ$ of Zn is more negative than that of Fe, therefore, Zn will be oxidised to $Z{{n}^{2+}}$ ions while $F{{e}^{2+}}$ ions will be reduced to Fe. In other words, Fe will not reduce $Z{{n}^{2+}}$ ions. (ii) Since $E{}^\circ$ of Fe is more negative than that of Ni, therefore, Fe will be oxidized to $F{{e}^{2+}}$ ions while $N{{i}^{2+}}$ ions will be reduced to Ni. Thus, Fe reduces $N{{i}^{2+}}$ ions.