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

In the alumino-thermite process,$Al$ acts as

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: The reduction of a metal oxide is easier if the metal formed is in liquid state than solid state.
Reason $R$: The value of $\Delta G^{\ominus}$ becomes more on negative side as entropy is higher in liquid state than solid state.
In the light of the above statements,choose the most appropriate answer from the options given below.

Heating a mixture of $Cu_2O$ and $Cu_2S$ will give:

Formation of metallic copper from the sulphide ore in the commercial thermo-metallurgical process essentially involves which one of the following reactions as the major reaction?

The cyanide process is used in the extraction of: