Cast iron is used for the manufacture of

Thermite is a mixture of

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 $\Delta G^{\ominus}$.

Although thermodynamically feasible,in practice,magnesium metal is not used for the reduction of alumina in the metallurgy of aluminium. Why?

Which of the following statements is not correct about the Ellingham diagram?

For the formation of which compound in the Ellingham diagram does $\Delta G^{\circ}$ become more and more negative with an increase in temperature?