Tests for anions and cations

• 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 first step in the halide test?

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

  Add silver nitrate
• How does the color of the precipitate indicate the halide present?

  Different halides form 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 process for testing for sulfates?

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

  1. Add dilute nitric acid to remove impurities
  2. Add silver nitrate solution
  3. Observe the color of the precipitate
• How do the tests for carbonates, sulfates, and halides differ?

  • Carbonates: Use hydrochloric acid and lime water
  • Sulfates: Use hydrochloric acid and barium chloride
  • Halides: Use nitric acid and silver nitrate