we can study the chioe of a reducing agent paticular case using ellingham digram , it is evident from th diagram that metals for which the standard free energy of formation oftheir oxides is more nagative can redue those metal oxides for which the standard free energy of formataion of their erespective oxides is less nagative it means that any metal will reduce the oxides of other metals which lie above itin the Elingham digam this is because the standar free energy change `(Delta _(r)G^(@))` of the combined redox eraction will be neagative by an amount equal to the difference in `Delta _(f)G^(@)` of the metal oxides thus both AL and Zn can reduce FeO to Fe but Fe cannot reduce `Al_(2)O_(3)` to Al an dZnP to Zn in the same way ,G can reduce An O to Zn but not CO.
Note:- Only that reagent will be preferred as reducing agent which lead to decocase i free energy value `(DeltaG^(@))` at a cetsin specific temperature .
