$Pb$ and $Sn$ are extracted from their chief ores by:

In the electrolytic reduction of alumina,why is cryolite $(Na_3AlF_6)$ primarily added?

Which of the following is slag?

Given are two statements,one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Magnesium can reduce $Al_{2}O_{3}$ at a temperature below $1350^{\circ} C$,while above $1350^{\circ} C$ aluminium can reduce $MgO$.
Reason $R$: The melting and boiling points of magnesium are lower than those of aluminium.
In light of the above statements,choose the most appropriate answer from the options given below:

State the role of silica in the metallurgy of copper.

What is blister copper?