Question

In isolation of which one of the following metals from their ores, the use of cyanide salt is not commonly involved?

Answer 1

In the extraciton of Silver and Gold, $NaCN$ is used to leach the metal.
$4Au\left(s\right)+8C{N}^{-}\left(aq\right)+2H_{2}O+O_2\left(g\right)\to 4\left[Au\right(CN{)}_2{]}^{-}\left(aq\right)+4O{H}^{-}\left(aq\right)$
$2\left[Au\right(CN{)}_2{]}^{-}\left(aq\right)+Zn\to 2Au\left(s\right)+\left[\right(Zn\left(CN{)}_4\right){]}^{2-}\left(aq\right)$

During extraction of $Zn$, $NaCN$ is used as a depressant during the froth floatation of $ZnS$