C4.2.3 - Detecting Anions Flashcards
What is formed when barium ions react with sulfate ions?
White insoluble barium sulfate
Describe how you would detect sulfate ions.
Add a few drops of hydrochloric acid to the solution, then a few drops of barium chloride. If the solution turns white, sulfate ions are present
Why does barium sulfate turn white?
A white precipitate is formed
What do hydrogen ions from dilute acids react with to form carbon dioxide and water?
Carbonate ions
Are most carbonates soluble?
No
Describe how you would detect carbonate ions.
Add a few drops of dilute hydrochloric/nitric acid to the solution, if it begins to bubble, carbonate ions are present. You can confirm the gas is carbon dioxide by bubbling it through limewater.
Describe how you would detect halide ions.
Add a few drops of nitric acid the solution, then add a few drops of silver nitrate solution. If the solution changes colour, a halide ion is present
What is the colour of the precipitate form if chloride ions are present?
white
What is the colour of the precipitate form if bromide ions are present?
cream
What is the colour of the precipitate form if iodide ions are present?
yellow