What are carbonate ions and how can you recognize them?
Well, carbonate ions are represented by
And how to demonstrate the presence of
Well, you must acidify the solution, and collect the evolved carbon dioxide.
The reactions that occur here are (i):
Precipitation of calcium carbonate is not straightforwardly observed, and if you do this in the lab, it is a good idea to use authentic carbonates so that you know for what you are looking.
The alkaline earths (Group 2) form binary carbonates that are (reasonably) insoluble in water.