In the extraction of copper from its sulphide ore,the slag is formed by adding which of the following?

In the extraction of copper from its sulphide ore,the metal is formed by the reduction of $Cu_2O$ with:

Which one of the following metals is extracted by thermal reduction process?

Which of the following furnaces can achieve the highest temperature?

In the metallurgical process of aluminium,cryolite $(Na_3AlF_6)$ is mixed with alumina $(Al_2O_3)$ in its molten state,because it

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 $\Delta G^{\ominus}$.