Test For Anions

• What are anions?

  Negatively charged ions
• What tests are covered for anions in the video?

  • Test for carbonate ions
  • Test for sulfate ions
  • Test for halide ions
• What happens when a carbonate reacts with an acid?

  It forms a salt, carbon dioxide, and water
• How can you test for carbonates in a solution?

  Add dilute hydrochloric acid and lime water
• What indicates a positive test for carbonates?

  Lime water turns cloudy
• What is the first step in the sulfate test?

  Add dilute hydrochloric acid
• Why do we add dilute hydrochloric acid in the sulfate test?

  To remove carbonate or sulfite impurities
• What forms when barium ions react with sulfate ions?

  Barium sulfate, a white precipitate
• What is the second step in the sulfate test?

  Add barium chloride solution
• What is the test for halide ions?

  Add dilute nitric acid and silver nitrate
• What is the purpose of adding dilute nitric acid in the halide test?

  To remove carbonate and sulfite impurities
• How does the precipitate color differ among halide ions?

  Chloride is white, bromide is cream, iodide is yellow
• What is the precipitate formed with chloride ions?

  Silver chloride, a white precipitate
• What is the precipitate formed with bromide ions?

  Silver bromide, a cream precipitate
• What is the precipitate formed with iodide ions?

  Silver iodide, a yellow precipitate
• What is the overall process for testing for anions?

  1. Test for carbonates:

  • Add dilute hydrochloric acid
  • Check for cloudy lime water

  1. Test for sulfates:

  • Add dilute hydrochloric acid
  • Add barium chloride, check for white precipitate

  1. Test for halides:

  • Add dilute nitric acid
  • Add silver nitrate, check precipitate color
• What should you do if you find a positive test result for carbonates?

  Confirm presence of carbonates in the sample
• What should you do if you see a white precipitate in the sulfate test?

  Confirm presence of sulfate ions in the sample
• What should you do if you see a cream precipitate in the halide test?

  Confirm presence of bromide ions in the sample
• What should you do if you see a yellow precipitate in the halide test?

  Confirm presence of iodide ions in the sample