Question

Which of the Following Process Involves Smelting?

• A. $2\mathrm{PbS}+3{\mathrm{O}}_2\to 2{\mathrm{PbO}}_2+2{\mathrm{SO}}_2$
• B. ${\mathrm{Al}}_2{\mathrm{O}}_3.2{\mathrm{H}}_2\mathrm{O}\to {\mathrm{Al}}_2{\mathrm{O}}_3+2{\mathrm{H}}_2\mathrm{O}$
• C. ${\mathrm{Fe}}_2{\mathrm{O}}_3+\mathrm{CO}\to 2\mathrm{Fe}+2{\mathrm{CO}}_2$
• D. ${\mathrm{Cr}}_2{\mathrm{O}}_3+2\mathrm{Al}\to {\mathrm{Al}}_2{\mathrm{O}}_3+2\mathrm{Cr}+\mathrm{Heat}$

Answer 1

The correct option is C

${\mathrm{Fe}}_2{\mathrm{O}}_3+\mathrm{CO}\to 2\mathrm{Fe}+2{\mathrm{CO}}_2$

Explanation for correct option:

C. ${\mathrm{Fe}}_2{\mathrm{O}}_3+\mathrm{CO}\to 2\mathrm{Fe}+2{\mathrm{CO}}_2$

Smelting of iron:

• During the extraction of iron, the reduction of iron oxides takes place in the blast furnace. In this process, hot air is blown from the bottom of the furnace, and coke is burnt to raise the temperature up to $2200\mathrm{K}$ in the lower portion itself.
• The temperature is lower in the upper part. Thus, it is the lower part where the reduction of iron oxides $({\mathrm{Fe}}_2{\mathrm{O}}_3\mathrm{and}{\mathrm{Fe}}_3{\mathrm{O}}_4)$ takes place.
• The reactions taking place in the lower temperature range $(500-800\mathrm{K})$in the blast furnace are:
• When Iron(II)oxide $\left({\mathrm{Fe}}_2{\mathrm{O}}_3\right)$ reacts with carbon monoxide it will form Ferrosoferric oxide $\left({\mathrm{Fe}}_3{\mathrm{O}}_4\right)$and carbon dioxide $\left({\mathrm{CO}}_2\right)$
  $3{\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)+\mathrm{CO}\left(\mathrm{g}\right)\to 2{\mathrm{Fe}}_3{\mathrm{O}}_4\left(\mathrm{s}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)$
• Ferrosoferric oxide reacts with carbon monoxide to form iron and carbon dioxide.
  ${\mathrm{Fe}}_3{\mathrm{O}}_4\left(\mathrm{s}\right)+4\mathrm{CO}\left(\mathrm{g}\right)\to 3\mathrm{Fe}\left(\mathrm{s}\right)+4{\mathrm{CO}}_2\left(\mathrm{g}\right)$
• Ferric oxide reacts with carbon monoxide to form the ferrous oxide and carbon dioxide as products.
  ${\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)+\mathrm{CO}\left(\mathrm{g}\right)\to 2\mathrm{FeO}\left(\mathrm{s}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)$
• The reactions taking place in the higher temperature range $(900-1500\mathrm{K})$ in the blast furnace are:
• Coke(C) when burnt with carbon dioxide gives carbon monoxide.
  $\mathrm{C}\left(\mathrm{s}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)\to 2\mathrm{CO}\left(\mathrm{g}\right)$
• When ferrous oxide reacts with carbon monoxide it gives out iron and carbon dioxide.
  $\mathrm{FeO}\left(\mathrm{s}\right)+\mathrm{CO}\left(\mathrm{g}\right)\to \mathrm{Fe}\left(\mathrm{s}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)$
• The silicate impurity of the ore is removed as slag by calcium oxide $\left(\mathrm{CaO}\right)$, which is formed by the decomposition of limestone $\left({\mathrm{CaCO}}_3\right)$.
  ${\mathrm{CaCO}}_3\left(\mathrm{s}\right)\to \mathrm{CaO}\left(\mathrm{s}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)$
• Calcium oxide reacts with Silicon dioxide to form Calcium silicate$\left({\mathrm{CaSiO}}_3\right)$ commonly known as slag.
  $\mathrm{CaO}\left(\mathrm{s}\right)+{\mathrm{SiO}}_2\left(\mathrm{s}\right)\to {\mathrm{CaSiO}}_3\left(\mathrm{s}\right)$

Explanation for incorrect options:

The reaction involves smelting ${\mathrm{Fe}}_2{\mathrm{O}}_3+\mathrm{CO}\to 2\mathrm{Fe}+2{\mathrm{CO}}_2$. Thus, options A, B, and D are incorrect.

Hence, the correct option is C i.e. ${\mathrm{Fe}}_2{\mathrm{O}}_3+\mathrm{CO}\to 2\mathrm{Fe}+2{\mathrm{CO}}_2$.