Resolved Question To determine the amount of sulfur (as sulfate) in a sample of lawn food? Sulfur in the form of sulfate is another important plant nutrient and is there- fore found in many fertiliser preparations. As sulfates easily form precipitates with suitable metal cations, a gravi- metric method based on this feature is a common way to analyse for sulfate. The usual metal ion used to form such a precipitate is barium, owing to the very low solubility of barium sulfate. The equation for this reaction is: Ba2+(aq) + SO42-(aq) --- &gt;BaSO4(s) AIM To determine the amount of sulfur (as sulfate) in a sample of lawn food. 1.Grind up some lawn food in a mortar and pestle, then accurately weigh out about 1.00 g. 2. Add this to about 100 mL of distilled water and dissolve as much as possible. 3. Filter the solution into a 400 mL (or larger) beaker. Wash the residue in the filter paper with several portions of distilled water. 4. Add about 5 mL of 1 mol L?1 hydrochloric acid to the filtrate followed by sufficient distilled water to give a total volume of 200 mL. 5. Heat to near boiling and then add about 15 mL of the barium chloride solution, stirring throughout. 6. Allow the precipitate to settle and then add a few drops of the barium chloride solution. If a precipitate forms, add a further 2 mL of the barium chloride solution. Repeat this step until no further precipitate forms. 7.