The reduction of an oxide by aluminium is called:

In the electrolysis of alumina $(Al_2O_3)$,cryolite $(Na_3AlF_6)$ is added to:

In which of the following metallurgical processes is no external reducing agent required?

Suggest a condition under which magnesium could reduce alumina. The two equations are:
$(a)$ $\frac{4}{3} Al + O_2 \rightarrow \frac{2}{3} Al_2O_3$
$(b)$ $2 Mg + O_2 \rightarrow 2 MgO$

In a blast furnace,iron oxide is reduced by:

Furnaces are lined with $CaO$ because