Their ions are called halide ions e.g. chloride, Cl-. You can test for them using silver nitrate solution.

The oxalate anion is donating electrons to the vacant 3d and 4s orbitals on iron. The potassium and chloride ions are spectator ions. (see your textbook for a discussion of Lewis Acids and Bases.) ...

eg identify an unknown compound using cation tests, anion tests and flame tests A teacher adds a few drops of universal indicator solution to a big container of water. She then adds a small piece ...