In the electrolysis of alumina $(Al_2O_3)$,cryolite $(Na_3AlF_6)$ is added to:

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:

In the cyanide process involving extraction of silver,zinc is used industrially as an

$Pb$ and $Sn$ are extracted from their chief ores by:

In the alumino thermite process,$Al$ acts as

Flux is used to remove