BaSO3 combines with HCl aq to form BaCl2 +H2O and SO2 but BaSO4 is insoluble and does nort react with HCl as it is a salt of strong acid than HCl. Solution BaSO3 combines with HCl aq to form BaCl2 +H2O and SO2 but BaSO4 is insoluble and does nort react with HCl as it is a salt of strong acid than HCl..