When compared to $\Delta G^{\circ}$ for the formation of $Al_{2}O_{3}$,the $\Delta G^{\circ}$ for the formation of $Cr_{2}O_{3}$ is

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 of the following is an acidic flux?

The reaction occurring in the final stage of the extraction of copper from copper pyrites in a Bessemer converter is:

What is the purpose of adding $Na_3AlF_6$ to $Al_2O_3$ during electrolysis?

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