A flux is often added to remove impurities from an ore in a blast furnace. In the reaction CaO + -> — Metallurgy and Isolation of Elements Chemistry Question

💡 Solution & Explanation

# Solution **Understanding Flux and Slag in Blast Furnace:** 1. **Flux definition**: A substance added intentionally to remove impurities (gangue). In iron smelting, **CaO (limestone/quicklime) is the flux**. 2. **Gangue identification**: The main impurity in iron ore is **$SiO_2$** (silica), which remains after ore processing. 3. **Slag formation**: When flux reacts with gangue: $$\text{CaO} + \text{SiO}_2 \rightarrow \text{CaSiO}_3$$ The product **$CaSiO_3$ (calcium silicate) is the slag** — the fused mass that separates from molten iron and can be easily removed. 4. **Role assignment**: - **Flux** = CaO (the added substance that does the removing) - **Slag** = $CaSiO_3$ (the waste product formed) **Answer B** correctly identifies: - **Flux: CaO** - **Slag: $CaSiO_3$** This removes the $SiO_2$ impurity by converting it into a fusible, separable slag that floats above the denser molten iron.