The sodium sulphate solution was digested to break the bonds in the solution in order to make the sulphate in the solution free to precipitate with the BaCl2 to form BaSO4

The sodium sulphate solution was digested to break the bonds in the solution in order to make the sulphate in the solution free to precipitate with the BaCl2 to form BaSO4. The barium sulphate precipitate was washed with warm distilled water to free the Cl- ion in the precipitate. Drops of AgNO3 was added in drop wise, if AgCl precipitate is formed then it indicates that the BaSO4 precipitate needs further washing. Then the precipitate and filter paper was heated until its weight became constant. Heating process removed all the solvent, adsorbed electrolytes and any volatile species that was carried down with the precipitate.