In the $Hall-Heroult$ process,aluminium is formed at the cathode. The cathode is made out of

Thermite is a mixture of $X$ parts of ferric oxide and $Y$ parts of aluminium powder. $X, Y$ respectively are

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:

Which of the following is electrolyzed for the extraction of aluminum?

Silica is added to roasted copper ores during extraction in order to remove

The Bessemer converter is used in the manufacture of: