CaSO3↓ + H2SO4 -> CaSO4 + SO2↑ + H2O — Redox Reactions and Volumetric Analysis Chemistry Question

💡 Solution & Explanation

Step 1: Calcium sulfite (CaSO3↓) is an insoluble precipitate. Step 2: Addition of sulfuric acid decomposes the sulfite, releasing sulfur dioxide gas (SO2↑) and forming calcium sulfate. Step 3: Even though calcium sulfate is sparingly soluble, the textbook answer key classifies this dissolution/decomposition reaction as a precipitate dissolution reaction (type B), corresponding to option (b).