Anion Test: Carbonate, Sulfate, Halide Flashcards
What is the carbonate test?
All metal carbonates produce CO2 gas when added to acid (Carbonate + Acid -> Salt + Water + CO2)
Add a few drops of dilute hydrochloric acid to the carbonate. If carbonate ions are present, bubbles of gas (CO2) can be produced.
You can confirm that the gas is carbon dioxide by bubbling it through limewater, which should turn cloudy.
What is the Sulfate test?
Add a few drops of dilute HCl, to remove any carbonate ions.
Then add Barium Chloride Solution (BaCl2) (aq).
If Sulfate ions are present, a white precipitate is produced. The white precipitate is barium Sulfate, which is insoluble.
What is the halide test?
Add dilute nitric acid, to dissolve the substance and remove any carbonate ions.
Add a few drops of silver nitrate solution (AgNo3) (aq).
A precipitate will be formed if a halide is present. (Note: Flouride will not form a precipitate, because silver fluoride is soluble).
The precipitate formed is either silver chloride, silver bromide, or silver iodide.
What are the colours of the halides in an anion test for halides?
Chloride: White precipitate formed
Bromide: Cream Precipitate formed
Iodide: Yellow precipitate formed
