Which among the following is used as flux in the extraction of iron from oxide ores?

In the process of leaching of gold by cyanide,what are the complexes $X$ and $Y$ respectively?
$4Au(s) + 8CN^-(aq) + 2H_2O(aq) + O_2(g) \to 4[Au(CN)_2]^-(aq) + 4OH^-(aq)$
$2[Au(CN)_2]^-(aq) + Zn(s) \to [Zn(CN)_4]^{2-}(aq) + 2Au(s)$
$X$ and $Y$ are:

The 'Hydrometallurgy' process is used for the extraction of which metals?

Given below are two statements.
Statement $I$: According to the Ellingham diagram,any metal oxide with higher $\Delta G^{\circ}$ is more stable than the one with lower $\Delta G^{\circ}$.
Statement $II$: The metal involved in the formation of oxide placed lower in the Ellingham diagram can reduce the oxide of a metal placed higher in the diagram.
In the light of the above statements,choose the correct answer from the options given below.

The function of fluorspar in the electrolytic reduction of alumina dissolved in fused cryolite $(Na_3AlF_6)$ is:

Which of the following conditions favours the reduction of a metal oxide to metal?