Slag formation in blast furnace iron extraction

Steps:

• Blast furnace reduces iron ore (Fe2O3) with CO and removes impurities as slag.
• Limestone decomposes to CaO, which reacts with silica (SiO2) impurity from ore.
• This forms calcium silicate slag: SiO2 + CaO → CaSiO3.
• Compare options to identify the matching slag reaction.

Why C is correct:

• It depicts the exact reaction of silica (SiO2) with lime (CaO) to produce slag (CaSiO3), essential for purifying molten iron.

Why the others are wrong:

• A: Reduction of iron oxide by CO, which occurs but is not the slag-forming step.
• B: Same as C but with reversed reactant order; standard form starts with SiO2.
• D: Forms sodium silicate using NaOH, unrelated to blast furnace process.

Final answer: C