In which furnace is pig iron produced? State its impurities.

During the electrolytic reduction of alumina,the reaction at the cathode is:

The blast furnace is primarily used for........

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:

Alumino-thermic process is used for the extraction of metals,whose oxides are

In the manufacture of steel,the Bessemer converter contains a lining of: