Converting insoluble barium carbonate to barium sulfate via acid dissolution and precipitation Steps:

• Dissolve barium carbonate in dilute hydrochloric acid to form soluble barium chloride and release carbon dioxide gas.
• Add dilute sulfuric acid to the barium chloride solution, causing insoluble barium sulfate to precipitate.
• Filter the mixture to separate the barium sulfate precipitate from the solution.
• Crystallize the precipitate from hot water or wash and dry it to obtain a pure sample.

Why A is correct:

• Barium carbonate (BaCO3) is insoluble in water (Ksp ≈ 5.1 × 10⁻¹⁰) but reacts with HCl via BaCO3 + 2HCl → BaCl2 + H2O + CO2, then BaCl2 + H2SO4 → BaSO4↓ + 2HCl, yielding pure BaSO4 precipitate.

Why the others are wrong:

• B: BaCO3 does not dissolve in water, so no barium ions available for reaction with sulfuric acid.
• C: Identical issue to B; dissolution in water fails, preventing precipitation.
• D: Same solubility problem as B and C; filtering and washing cannot produce BaSO4 without prior dissolution.

Final answer: A