Test for anions

• What is the focus of the practical tests mentioned?

  Testing for anions
• What is the purpose of identifying ions in mystery compounds?

  To determine the composition of the compounds
• What ions are being tested for using silver nitrate solution?

  Halide ions
• What are the steps to test for halide ions using silver nitrate solution?

  1. Add dilute nitric acid to the sample.
  2. Add a few drops of silver nitrate solution.
  3. Observe the color of the precipitate formed.
• What color precipitate indicates the presence of chloride ions?

  White precipitate
• What color precipitate indicates the presence of bromide ions?

  Cream precipitate
• What color precipitate indicates the presence of iodide ions?

  Yellow precipitate
• What is the reaction for the formation of silver chloride?

  • Reaction:

  $Ag^+$$(aq) +$$Cl^-(aq) \rightarrow AgCl(s)$

  • Indicates presence of chloride ions.
• What is the reaction for the formation of silver bromide?

  • Reaction:

  $Ag^+$$(aq) +$$Br^-(aq) \rightarrow AgBr(s)$

  • Indicates presence of bromide ions.
• What is the reaction for the formation of silver iodide?

  • Reaction:

  $Ag^+$$(aq) +$$I^-(aq) \rightarrow AgI(s)$

  • Indicates presence of iodide ions.
• What should be added to test for carbonate ions in solution?

  Dilute acid
• What happens when carbonate ions react with dilute acid?

  They produce carbon dioxide gas
• What is the reaction for carbonate ions with dilute acid?

  • Reaction:

  $CO_3^{2-} +$$2H^+$$\rightarrow CO_2(g) +$$H_2O$

  • Indicates presence of carbonate ions.
• How can you check if a gas produced is carbon dioxide?

  By bubbling it through limewater
• What indicates that the gas is carbon dioxide when passed through limewater?

  Limewater turns milky
• What is the test for carbon dioxide gas?

  • Pass gas through limewater.
  • Observation: Limewater turns milky.
• What happens if carbonate ions are present in the mixture with dilute acid?

  The mixture will fizz due to gas release
• What is the visual indication of the presence of carbon dioxide in the test?

  Milky limewater
• Where is the test for carbon dioxide covered?

  On the next page
• What are the general steps to test for anions?

  1. Identify the type of anion.
  2. Use appropriate reagents.
  3. Observe precipitate color changes.
• What is the chemical formula for carbon dioxide?


  CO₂
• What is produced when carbon dioxide reacts with water?

  Carbonic acid
• How can you check if a gas is carbon dioxide?

  By bubbling it through lime water
• What happens to lime water if carbon dioxide is present?

  It turns milky
• What is the test for sulfate ions using barium chloride solution?

  Formation of a white precipitate
• What is the procedure to test for sulfate ions in solution?

  1. Add dilute hydrochloric acid to the sample.
  2. Add barium chloride solution.
  3. Observe for a white precipitate.
• What does adding dilute hydrochloric acid do in the sulfate test?

  It prevents precipitation reactions
• Why is it important that each test for ions is unique?

  To ensure accurate identification of ions
• What would happen if different ions gave the same response in tests?

  You wouldn't know which ion is present
• What is the significance of knowing the tests for all ions on the page?

  It helps in identifying unknown samples
• What is the result of adding barium ions to a solution containing sulfate ions?

  Barium sulfate precipitate forms
• Why is it important to have unique results for each test?

  To avoid confusion in identifying ions
• What would be a consequence of having the same response for different ions?

  It would lead to misidentification of ions
• What is the importance of knowing what ions are present in a sample?

  It aids in chemical analysis and reactions