In the equation $4M + 8CN^{-} + 2H_2O + O_2 \to 4[M(CN)_2]^- + 4OH^{-}$,identify the metal $M$.

Copper sulphate is commercially made from copper scraps by:

Name the metal $M$ which is extracted on the basis of following reactions:
$4M + 8CN^{-} + 2H_2O + O_2 \rightarrow 4[M(CN)_2]^{-} + 4OH^{-}$
$2[M(CN)_2]^{-} + Zn \rightarrow [Zn(CN)_4]^{2-} + 2M$

Blister copper is extracted from copper pyrites. After removal of slag $FeSiO_3$,blister copper is obtained by

Which is the main reducing agent for extraction in a blast furnace?

Explain the theory of reduction of metal oxides with carbon as a reducing agent,or explain the role of a reducing agent in the reduction of metal oxides.