During the extraction of $Fe$,which reaction is performed in the combustion zone?

Copper is extracted from copper pyrites by

The electrolytic method of reduction is employed for the preparation of metals that

Which one of the following oxides is reduced by water gas to obtain the metal during its extraction?

Which of the following statements is not correct?
$1$. Reduction of alumina to give aluminium by magnesium is thermodynamically feasible.
$2$. The point of intersection of $Al_2O_3$ and $MgO$ curves in Ellingham diagram is below $1665 \ K$.
$3$. Use of magnesium as reducing agent in metallurgy of aluminium is economical.
$4$. Ellingham diagram represents the graphical plot of Gibbs energy vs temperature for the formation of the oxides of common metals and reducing agents.

When alumina is heated with carbon in a nitrogen atmosphere,the products are