Refractory materials are generally used in furnaces because

In the metallurgical extraction of zinc from $ZnO$,the reducing agent used is:

Which among the following processes occurs at $1500 \ K$ in a blast furnace for the extraction of iron?

In the extraction of copper from its sulphide ore,metal is finally obtained by the oxidation of cuprous sulphide with

Extraction of aluminium from bauxite ore,reduction is carried out by

The value of ${\Delta _r}{G^\Theta }$ for the formation of $Cr_2O_3$ is $-540 \, kJ \, mol^{-1}$ and that of $Al_2O_3$ is $-827 \, kJ \, mol^{-1}$. Is the reduction of $Cr_2O_3$ possible with $Al$?