Write the reaction equation: BaSO4 – BaCO3 – BaCl2 – BaSO4 – BaS

1) BaSO4 + Li2CO3 = BaCO3 + Li2SO4 (when barium sulfate interacts with lithium carbonate, barium carbonate and lithium sulfate are formed);

2) BaCO3 + 2HCl = BaCl2 + CO2 + H2O (when barium carbonate interacts with hydrochloric acid, barium chloride, carbon dioxide and water are formed);

3) BaCl2 + Na2SO4 = BaSO4 + 2NaCl (when barium chloride interacts with sodium sulfate, barium sulfate and sodium chloride are formed);

4) BaSO4 + 4C = BaS + 4CO (when barium sulfate interacts with carbon, barium sulfide and carbon monoxide are formed).