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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.
A
$CaO(s) + SiO_2(s) \rightarrow CaSiO_3(s)$
B
$2C(s) + O_2(g) \rightarrow 2CO(g)$
C
$Fe_2O_3(s) + 3CO(g) \rightarrow 2Fe(l) + 3CO_2(g)$
D
$CaCO_3(s) \rightarrow CaO(s) + CO_2(g)$
Detailed Solution
In the blast furnace, limestone is added as a flux; it first decomposes: $CaCO_3 \rightarrow CaO + CO_2$
The basic oxide CaO (flux) then combines with the acidic impurity silica (gangue) to form fusible calcium silicate, which is the slag: $CaO + SiO_2 \rightarrow CaSiO_3$
The slag is lighter than molten iron, floats on it and is removed separately.
$2C + O_2 \rightarrow 2CO$ is the combustion of coke that supplies heat and the reducing agent, and $Fe_2O_3 + 3CO \rightarrow 2Fe + 3CO_2$ is the reduction of the ore.
Hence the slag-forming reaction is $CaO(s) + SiO_2(s) \rightarrow CaSiO_3(s)$.
The basic oxide CaO (flux) then combines with the acidic impurity silica (gangue) to form fusible calcium silicate, which is the slag: $CaO + SiO_2 \rightarrow CaSiO_3$
The slag is lighter than molten iron, floats on it and is removed separately.
$2C + O_2 \rightarrow 2CO$ is the combustion of coke that supplies heat and the reducing agent, and $Fe_2O_3 + 3CO \rightarrow 2Fe + 3CO_2$ is the reduction of the ore.
Hence the slag-forming reaction is $CaO(s) + SiO_2(s) \rightarrow CaSiO_3(s)$.