Testing for anions (negatively charged)

• 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 precipitate
• What color is the precipitate formed in a positive sulfate test?

  White precipitate
• What is the first step in the halide test?

  Add dilute nitric acid
• What is added in the second step of the halide test?

  Add silver nitrate
• What do silver ions react with in the halide test?

  Halide ions
• How does the color of the precipitate indicate the type of halide present?

  Different halides produce different colored precipitates
• What color precipitate does silver chloride form?

  White precipitate
• What color precipitate does silver bromide form?

  Cream precipitate
• What color precipitate does silver iodide form?

  Yellow precipitate
• What is the procedure for testing for carbonates?

  1. Add dilute hydrochloric acid to the sample.
  2. Collect any gas produced.
  3. Bubble the gas through lime water.
  4. Observe if lime water turns cloudy.
• What is the procedure for testing for sulfates?

  1. Add dilute hydrochloric acid to remove impurities.
  2. Add barium chloride solution.
  3. Observe for white precipitate formation.
• What is the procedure for testing for halide ions?

  1. Add dilute nitric acid to remove impurities.
  2. Add silver nitrate solution.
  3. Observe the color of the precipitate formed.
• What are the differences in the tests for sulfates and halides?

  • Sulfate test uses barium chloride.
  • Halide test uses silver nitrate.
  • Sulfate test uses hydrochloric acid; halide uses nitric acid.