I am writing a lab report for chemistry about reactions with anions. One reaction we did was a reaction of calcium with a sulfate anion. 1 mL of an aqueous solution of sulfate was added to a test tube and 1/2 a mL of aqueous ammonia was added to the test tube. Then an aqueous solution of calcium was added to the test tube. The same test was performed with oxalate ion and carbonate ion, both of which formed a white precipitate. However, the sulfate ion did not produce a precipitate. I was wondering if maybe there was supposed to be a reaction and a precipitate was supposed to be formed?