Sunil Kumar FP
The thermodynamic factor helps usin choosinga suitable reducing agent for the reduction ofparticularmetal oxide to metal . The feasibility of thermal reduction can be predicted on the basisofΔG0Vs Tplots for the formation of oxides, known as Ellinghamdiagram . from the diagram it canbe predicted that metalsforwhichtheΔfG0( of their oxides) ismore negativecan reduce those metal oxides forwhich standard freeenergy offormationof theirrespective oxidesis lessnegative .In other words , a metal will reduce the oxidesof the other metals which lie above it in the Ellingham Diagrambecause the ΔfG0of the combined redox reaction will be negative by an amount equal to the difference in ΔfG0
ofthe two metal oxides .
For example, both Al and Zn can reduce FeO to Fe but Fe cannot reduce ZnO to Zn and Al2O3to Al .Similarly , Carbon can reduce ZnO to Znbut not CO . thusthe choice ofreducing agentin adepends onthermodynamic factor