identifying anions

Cards (24)

  • What is the formula for carbonate ions?
    CO32-
  • How can you confirm the presence of carbonate ions?
    Add dilute nitric acid and observe effervescence
  • What gas is evolved when carbonate ions react with acid?
    Carbon dioxide (CO2)
  • What does the reaction of carbonate ions with dilute nitric acid produce?
    CO2 and H2O
  • What is the test for confirming CO2 gas?
    Passing it through limewater
  • What happens to limewater when CO2 is present?
    It turns cloudy due to calcium carbonate
  • What is the formula for sulfate ions?
    SO42-
  • How can you confirm the presence of sulfate ions?
    Add dilute nitric acid and barium ions
  • What precipitate forms when sulfate ions react with barium ions?
    Barium sulfate (BaSO4)
  • What is the color of the precipitate formed from barium sulfate?
    White
  • What is the first step in identifying halide ions?
    Add dilute nitric acid dropwise
  • What is added after nitric acid to test for halide ions?
    Silver nitrate solution (AgNO3)
  • What color precipitate indicates the presence of chloride ions?
    White (AgCl)
  • What color precipitate indicates the presence of bromide ions?
    Cream (AgBr)
  • What color precipitate indicates the presence of iodide ions?
    Yellow (AgI)
  • How can you distinguish between silver halides using ammonia solutions?
    By observing solubility in dilute and concentrated NH3
  • Which silver halide is soluble in dilute ammonia?
    Silver chloride (AgCl)
  • Which silver halide is soluble in concentrated ammonia?
    Silver bromide (AgBr)
  • Which silver halide is not soluble in either dilute or concentrated ammonia?
    Silver iodide (AgI)
  • Why is it important to eliminate interfering ions in tests?
    To avoid false positives in negative ion tests
  • How do carbonate ions interfere with sulfate tests?
    They precipitate as white barium carbonate
  • How do sulfate ions interfere with halide tests?
    They precipitate as white silver sulfate
  • What can introduce additional chloride ions leading to false positives?
    Hydrochloric acid
  • What is the correct order for testing negative ions?
    Carbonate, sulfate, halides