text: Some salts are insoluble in water. For example BaS2 is insoluble. You can make it by adding two soluble salts solutions togeter. ie: BaCl2 (aq.) + Na2S (aq.) --> BaS2 (ppt.) + Na+(aq.) + Cl- (aq.). The (aq.) means dissolved in water, (ppt.) means precipitate or solid formed. Good luck!