Chromium is obtained by reducing concentrated chromite ore with

Explain the theory of reduction of metal oxides with carbon as a reducing agent,or explain the role of a reducing agent in the reduction of metal oxides.

During the extraction of gold,the following reactions take place: $4Au + 8CN^{-} + 2H_2O + O_2 \longrightarrow 4[Au(CN)_2]^{-} + 4OH^{-}$ and $2[Au(CN)_2]^{-} + Zn \longrightarrow [Zn(CN)_4]^{2-} + 2Au$. $X$ and $Y$ are respectively:

The metal which is extracted by oxidation and subsequent reduction from its ore is:

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:

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