The correct option for the question regarding which reaction does not take place in the smelting of iron in a blast furnace is **C. 3Fe(s) + 2O2(g) → FeO4(s)**. ### Detailed Explanation: 1. **Understanding the Process of Smelting Iron:** - Smelting is a process used to extract metal from its ore by using heat and a chemical reducing agent. In the case of iron, the primary ore is iron oxide (Fe2O3 or Fe3O4). - A blast furnace is a large structure where iron ore, coke (carbon), and limestone (calcium carbonate) are added. The coke serves as a fuel and reducing agent, while limestone helps remove impurities. 2. **Analyzing Each Reaction:** - **Option A: CaCO3(s) → CaO(s) + CO2(g)** - This reaction represents the thermal decomposition of calcium carbonate into calcium oxide (lime) and carbon dioxide. This reaction occurs in the blast furnace as limestone is heated to produce lime, which helps in the formation of slag by combining with impurities. - **This reaction does take place in the blast furnace.** - **Option B: C(s) + O2(g) → CO2(g)** - This reaction describes the combustion of carbon (from coke) in the presence of oxygen to produce carbon dioxide. This reaction is crucial in the blast furnace as it provides the heat necessary for the smelting process and generates carbon dioxide, which can further react with iron oxides to reduce them to iron. - **This reaction does take place in the blast furnace.** - **Option C: 3Fe(s) + 2O2(g) → FeO4(s)** - This reaction suggests that solid iron (Fe) reacts with oxygen to form iron tetroxide (FeO4). However, this is not a valid reaction in the context of iron smelting. Iron typically forms oxides such as FeO (wüstite) or Fe2O3 (hematite) but not FeO4. The formation of FeO4 is not a common or stable compound in the smelting process. - **This reaction does NOT take place in the blast furnace.** - **Option D: SiO2(s) + CaO(s) → CaSiO3(s)** - This reaction represents the formation of calcium silicate (slag) from silica and lime. This is an important reaction in the blast furnace as it helps to remove impurities from the iron ore, forming a liquid slag that can be removed. - **This reaction does take place in the blast furnace.** 3. **Why Other Options Are Incorrect or Weaker:** - Options A, B, and D are all valid reactions that occur in the blast furnace during the smelting of iron. They contribute to the overall process of reducing iron ore and removing impurities. In contrast, Option C is incorrect because it proposes a reaction that does not occur in the smelting process and involves a compound (FeO4) that is not relevant in this context. ### Summary of Key Points: - The blast furnace smelting process involves reactions that reduce iron oxides and remove impurities. - Valid reactions include the decomposition of limestone (A), combustion of coke (B), and formation of slag (D). - The reaction forming FeO4 (C) is not valid and does not occur in the smelting of iron. - Understanding the chemistry of the blast furnace is crucial for recognizing which reactions are relevant in iron production. This thorough understanding of the reactions involved in the blast furnace will help you in your studies and exams related to metallurgy and industrial chemistry.