How can 6m nitric acid be used to identify co2 3 ions dissolved in the same solution with so2 4 and po3 4 ions? 2. How can you distinguish between so2 4 and po3 4 if they are present in the same solution? 3. What would you do and how would you know that a precipitate contained either agcl, or agi, or both? 4. Why should you test for the presence of no 3 ions in a solution before testing for the presence of cl and i ions in that solution? 5. Why should a person not test for the presence of no 3 ions in a solution that he or she plans to subsequently test for the presence of sulfate ions, so2 4 ?