Testing for Anions

Testing for Anions

Anions are negative ions

Testing for carbonates:

To see if a gas is carbon dioxide you can bubble it through limewater and the limewater will turn milky. You can use this for carbonates because they react with dilute acids to form carbon dioxide:

Acid + Carbonate -----------> Salt + Water + Carbon dioxide

Some carbonates change colour when they decompose:

• Method: put one spatula of carbonate into a test tube and heat strongly, then cool
• Copper carbonate turns from green to black and stays black when cool
• CuCO3 (green) -------------> CuO (black) +…