The choice of a reducing agent in a particular case depends on thermodynamic factor. How far do you agree with this statement ? Support your opinion with example.

Explanation

The thermodynamic factor helps us in choosing a suitable reducing agent for the reduction of a particular metal oxide to metal. The feasibility of thermal reduction can be predicted on the basis of `Delta_f G^@` vs T plots for the formation of oxides, known as Ellingham diagram. From the diagram, it can be predicted that metals for which the standard free energy of formation of their oxides is more negative can reduce those metal oxides for which the standard free energy of formation of their respective oxides is less negative. In other words , a metal will reduce the oxides of other metals which lie above it in Ellingham diagram because the standard free energy change, `(Delta_r G^@)` of the combined redox reaction will be-ve by an amount equal to the difference in `Delta_r G^@` of the two metal oxides. For example , both Al and Zn can reduce FeO to Fe but Fe cannot reduce `Al_2 O_3` to Al or ZnO to Zn. Similarly, C can reduce ZnO to Zn but not CO. Thus, the choice of a particular reducing agent depends on thermodynamic factor.