In the processing of steel,which of the following allotropes of carbon is used?

The temperature at which carbon reduces $FeO$ into iron and produces $CO$ is:

Impure silver ore $+ CN^{-} + H_2O \xrightarrow{O_2} [X]^{-} + OH^{-}$
$[X]^{-} + Zn \longrightarrow [Y]^{2-} + Ag \text{ (pure)}$
The coordination numbers of the metals in $[X]$ and $[Y]$ are respectively

The final step for the extraction of copper from copper pyrite in the Bessemer converter involves the reaction:

When alumina is heated with carbon in a nitrogen atmosphere,the products are

In the process of extraction of gold,roasted gold ore reacts as follows. Identify the complexes $[X]$ and $[Y]$:
$\text{Roasted gold ore} + CN^{-} + H_2O \xrightarrow{O_2} [X] + OH^{-}$
$[X] + Zn \to [Y] + Au$