Identify the correct statements for the following reaction sequence:
$Ag + NaCN (0.5\%) + H_2O + O_2 \to \text{Soluble complex} \xrightarrow{Zn} B (\text{complex}) + Ag$

Which of the following is not added during the extraction of silver by the cyanide process?

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

Which of the following statements is not correct?
$1$. Reduction of alumina to give aluminium by magnesium is thermodynamically feasible.
$2$. The point of intersection of $Al_2O_3$ and $MgO$ curves in Ellingham diagram is below $1665 \ K$.
$3$. Use of magnesium as reducing agent in metallurgy of aluminium is economical.
$4$. Ellingham diagram represents the graphical plot of Gibbs energy vs temperature for the formation of the oxides of common metals and reducing agents.

Native silver metal forms a water soluble complex with a dilute aqueous solution of $NaCN$ in the presence of

In the process of obtaining cast iron from pig iron,the reverberatory furnace is lined with ..........