In the leaching of $Ag_2S$ with $NaCN$,a stream of air is also passed. This is because of:

Match List-$I$ (Substances) with List-$II$ (Processes) used for their production.

List-$I$ (Substances)	List-$II$ (Processes)
$(a)$ Sulphuric acid	$(i)$ Haber process
$(b)$ Steel	$(ii)$ Bessemer process
$(c)$ Sodium hydroxide	$(iii)$ Leblanc process
$(d)$ Ammonia	$(iv)$ Contact process

Choose the correct option for $a-b-c-d$.

Metals are extracted by other methods through the formation of complexes. The complexes formed in these methods are: $I$: Cyanide process,$II$: Mond process,$III$: Photographic fixing process.

Which of the following alloys contains $Ni$ metal?

The electrochemical extraction of aluminum from bauxite ore involves:

Among the reactions $(a) - (d)$,the reaction$(s)$ that does/do not occur in the blast furnace during the extraction of iron is/are:
$(a)$ $CaO + SiO_2 \rightarrow CaSiO_3$
$(b)$ $3 Fe_2O_3 + CO \rightarrow 2 Fe_3O_4 + CO_2$
$(c)$ $FeO + SiO_2 \rightarrow FeSiO_3$
$(d)$ $FeO \rightarrow Fe + \frac{1}{2} O_2$