Question

Extraction of copper is done from copper pyrites which contain small quantity of:
A. Zinc
B. iron
C. sodium
D. carbon

Answer 1

Hint: The principle ore from which the copper is extracted in a large amount is chalcopyrite. The chalcopyrite is commonly known as copper pyrite. The chemical formula of copper pyrite is $CuFe{S_2}$.

Complete step by step answer:
The copper is extracted from its ore which is commonly known as copper pyrite. The copper pyrite is known as chalcopyrite. The chemical formula of copper pyrite is $CuFe{S_2}$. In the extraction of metal from its ore first the ore is concentrated by the froth flotation process. The ore is crushed into fine particles and a suspension solution is formed in water. The collector is present which increases the non-wettability of metal and helps to form the froth. The oil present wet the metal and water wet the impurities. The froth is formed from where metal is skimmed and dried to obtain the metal. After concentrating the metal smelting of copper is done, the smelting is defined as the metallurgy process used to extract the base metal from its ore. In the copper smelting process, the concentrated ore is heated with silica, calcium carbonate and air in a furnace.
The reaction for the process is shown below.
$2CuFe{S_2} + 2Si{O_2} + 4{O_2} \to C{u_2}S + 2FeSi{O_3} + 3S{O_2}$
The copper obtained from this process is mixed with the slag which is then reduced to pure metal.
The reaction is shown below.
$C{u_2}S + {O_2} \to 2Cu + S{O_2}$
In the ore copper pyrite $CuFe{S_2}$, as a large amount of copper is extracted from the process of smelting, the metal which is present in low amounts is iron.
Therefore, the correct option is B.

Note:
The copper obtained is called Blister copper which is 98 to 99.5 % pure. The byproduct sulphur dioxide escapes from the copper and forms bubbles which burst when sulphur dioxide leaves. This is responsible for the blistery appearance of copper.