The following reactions take place in the blast furnace in the preparation of impure iron. Identify the reaction pertaining to the formation of the slag.
- Fe2O3(s) + 3CO(g) 2Fe(l) + 3CO2(g)
- CaCO3(s) CaO(s) + CO2(g)
- CaO(s) + SiO2(s) CaSiO3(s)
- 2C(s) + O2(g) 2CO(g)
Answer
(3) CaO(s) + SiO2(s) CaSiO3(s)
Solution
In the blast furnace, limestone decomposes to CaO, which acts as a flux and combines with the silica impurity (gangue) to form calcium silicate, the slag:
CaO + SiO2 CaSiO3 (slag)
The other reactions are reduction of the oxide (A), decomposition of limestone (B) and formation of the reducing agent CO (D).
Answer: (3)