The choice of reducing agent for metal oxide is decided by thermodynamic principles of metallurgy. `Delta G` must be negative. Ellingham diagram is a plot of `Delta_(f)G^(0)` vs T for the formation of oxides of various elements. All the plots slope upwards when temperature increases. Each plot is a straight line except when some change in phase takes place. A metal will reduce the oxide of other metals which lie above it in this diagram.
At a temperature below 1623 K. Al cannot reduce

Options

A. FeO
B. CrO
C. MgO
D. NiO

Answer

C

Explanation

AI can.t reduce MgO as Mg is more electropositive.