Aluminium is extracted from alumina $(Al_2O_3)$ by electrolysis of a molten mixture of

Who studied the plots of $\Delta G$ versus $T$?

Carbon cannot be used in the reduction of $Al_2O_3$ because

Case hardening is a process of heating steel in an atmosphere of:

The reduction of $Al$ oxide cannot be carried out by chemical reactions because .....

Observe the following statements:
Statement-$I$: The choice of reducing agent for the reduction of an oxide ore can be predicted by using Ellingham diagram,a plot of $\Delta G^{\ominus}$ vs $T$.
Statement-$II$: According to Ellingham diagram,metal oxide with higher $\Delta G^{\ominus}$ is more stable than the oxide with lower $\Delta G^{\ominus}$.