What is the reduction of $Cr_2O_3$ by heating it with aluminum called?

In the alumino thermite process,$Al$ acts as

Aluminium has a great affinity for oxygen and its oxidation is an exothermic process. This fact is made use of in

The purest form of iron is:

What is the role of the graphite rod in the electrometallurgy of aluminium?

Extraction of gold $(Au)$ involves the formation of complex ions $X$ and $Y$ as shown in the reaction: $\text{Gold ore}$ $\xrightarrow{CN^-, H_2O, O_2} HO^- + X$ $\xrightarrow{Zn} Y + Au$. $X$ and $Y$ respectively are: