Lead is mainly extracted by

The maximum temperature that can be achieved in a blast furnace is:

Which oxide formation according to the Ellingham diagram shows a graph with a sudden change in slope?

In the nitriding process of steel:

In the electrolytic reduction of alumina,why is cryolite $(Na_3AlF_6)$ primarily added?

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