An unknown compound is suspected to be a carbonate. What kind of chemical should be added to the compound to test this theory?

To test if an unknown compound is a carbonate, you should add an acid to it. This is because carbonates react with acids to produce carbon dioxide gas. A common acid to use for this test is dilute hydrochloric acid (HCl).

Here are the steps:

1. Place a small amount of the unknown compound in a test tube.
2. Add a few drops of dilute hydrochloric acid to the test tube.
3. Observe the reaction. If the compound is a carbonate, it will fizz or bubble as carbon dioxide gas is produced.

This is a simple and effective way to test for the presence of carbonates.