How do we test for negatively charged ions?

Testing for carbonate ions: dilute acid usually hydrochloric added to the compound, bubbles are given off caused by carbon dioxide Testing for sulfate ions: add a few drops of hydrochloric acid to remove the carbonate ions, then add a few drops of barium chloride solution, white barium precipitate forms Testing foe halide ions: add a few drops of dilute nitric acid to the sample to remove carbonate ions then add a few drops of dilute silver nitrate solution the halides form these precipitates: Chloride, Cl- White Bromide, Br- Cream Iodide, I- Yellow