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

After partial roasting,the sulphide of copper is reduced by

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

Leaching of gold with dilute aqueous solution of $NaCN$ in presence of oxygen gives complex $[A]$,which on reaction with zinc forms the elemental gold and another complex $[B]$. $[A]$ and $[B],$ respectively are ...... .

The type of iron obtained from a blast furnace in the extraction of iron is:

Which of the following elements is present as the impurity to the maximum extent in the pig iron?