$CN^{-}$ solution is used in the extraction of which metal?

The reduction of $Al$ oxide cannot be carried out by chemical reactions because .....

In the extraction of copper from copper pyrites,iron is removed as

Assertion : Extraction of iron metal from iron oxide ore is carried out by heating with coke.
Reason : The reaction,
$Fe_2O_{3(s)} \to Fe_{(s)} + 3/2 O_{2(g)}$ is a spontaneous process.

In the extraction of copper from its sulphide ore,the metal is formed by the reduction of $Cu_2O$ with:

Among the following,the main reactions occurring in the blast furnace during the extraction of iron from haematite are:
$i$. $Fe_2O_3 + 3CO \rightarrow 2Fe + 3CO_2$
$ii$. $FeO + SiO_2 \rightarrow FeSiO_3$
$iii$. $Fe_2O_3 + 3C \rightarrow 2Fe + 3CO$
$iv$. $CaO + SiO_2 \rightarrow CaSiO_3$