Question

# The form of iron obtained from the blast furnace is: A. Steel B. Cast iron C. Pig iron D. Wrought iron

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Hint:
The process of extracting iron is performed in a giant container which is known as a blast furnace, it is extracted from Iron ores one of the examples is haematite which is iron $\left( {III} \right)$ oxide,$F{e_2}{O_3}$. The oxygen must be removed from the iron$\left( {III} \right)$ oxide so that we can obtain iron, and such types of reactions are known as reduction reactions as there is a removal of oxygen.

Now, let’s learn about the extraction of iron in detail:
Iron ore is added from the top in the blast furnace with some carbon and limestone the blast furnace has a temperature of $500 - 800{\text{ }}K$, and this hot air is blown from the bottom, carbon is added in the form of coke and the coke is burned which gives the blast furnace a temperature of $2200{\text{ }}K$. At such high temperature the coke has a tendency to react with the oxygen present in the hot air which give carbon monoxide as a product, now the hot air moves upwards where the raw material we have added is coming from, and the Haematite is reduced by $CO$ to ferrous oxide $\left( {FeO} \right)$ and the reaction is as follows:
These are the reactions in the upper part of the blast furnace at a temperature of $500 - 800{\text{ }}K$;
$3F{e_2}{O_3} + CO \to 2F{e_3}{O_4} + C{O_2}$
$F{e_3}{O_4} + 4CO \to 3Fe + 4C{O_2}$
$F{e_2}{O_3} + CO \to 2FeO + C{O_2}$
These are the reactions in the lower part of the blast furnace at a temperature of $900 - 1500K$ ;
$C + C{O_2} \to 2CO$
$3FeO + C{O_2} \to Fe + C{O_2}$
And the limestone which is added with the ores is decomposed to $CaO$ which is used in removing the impurities such as silicate which in the form of slag, which can be easily removed from the molten Iron. The final product in Blast Furnace is about $3-4{\text{ }}\%$ of Carbon and small quantities of many other impurities such as sulfur, Silicon, etc. This is called Pig Iron. And is hard but brittle in nature and the impurities present in the product severely affects its strength.

Hence the Pig iron is formed. So, the correct answer is Pig iron Option C.

Note:To further reduce the carbon content of pig iron, the obtained metal is melted again with some coke and iron flakes in a blast furnace. This formed iron is known as Cast Iron and has a little less level of carbon which is $2 - 3\%$ as compared to the pig iron and is much harder in nature than the pig iron.