$Pb$ and $Sn$ are extracted from their ores by which of the following methods?

Cast iron is used for the manufacture of

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.

Matte contains mainly

In the electrolytic method of obtaining aluminium from purified bauxite,cryolite is added to the charge in order to

During the smelting of roasted copper ore,silica is added to remove: