Which one of the following is used as an acid flux in metallurgy?

When silica is present as an impurity in an ore,a/an ........ flux is required.

In the Mc Arthur Forest method,silver is extracted from the solution of $Na[Ag(CN)_2]$ by the use of:

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

Which among the following processes occurs at $1500 \ K$ in a blast furnace for the extraction of iron?

During the electrolytic reduction of alumina,the reaction at the cathode is: