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  • FREE 5-MIN Notes
    • 1. Experimental Techniques
    • 2. Methods of Purification
    • 3. Separation Techniques
    • 4. Qualitative Analysis
    • 5. Kinetic Particle Theory
    • 6. Atomic Structure
    • 7. Elements, Compounds, Mixtures
    • 8. Ionic Bonding
    • 9. Covalent Bonding
    • 10. Mole Concept
    • 11. Electrolysis
    • 12. Energy Changes
    • 13. Speed of Reaction
    • 14. Redox
    • 15. Acids and Bases
    • 16. Salts
    • 17. Ammonia
    • 18. Periodic Table
    • 19. Metals
    • 20. Air
    • 21. Fuels
    • 22. Organic Chemistry
    • 23. Macromolecules
  • Free Printables

4. Qualitative Analysis

Identification of ions and gases
  • An ionic compound contains a cation (positive ion) and an anion (negative ion)
  • To identify a compound, you will have to describe the tests carried out and the expected observations for both cation and anion.
 
Tests for Cations
  • Add aqueous sodium hydroxide dropwise first, then in excess.
  • Add aqueous ammonia  dropwise first, then in excess.
 
Differentiating Pb2+ and Al3+
Add aqueous potassium iodide. If Pb2+ is present, a bright yellow precipitate (lead(II) iodide) is formed. If Al3+ is present, no precipitate is formed and solution remains colourless.

Click here to download a FREE summary chart for Tests for Cations.

Tests for Anions

Click here to download a FREE summary chart for Tests for Anions.

Test for Gases
  • Hydrogen: Gas extinguishes a lighted splint with a ‘pop’ sound
  • Oxygen: Gas relights a glowing splint
  • Ammonia: Gas turned moist red litmus blue
  • Carbon dioxide: Gas forms white ppt when bubbled into limewater
  • Chlorine: Gas turns moist blue litmus red, then bleaches it
  • Sulfur dioxide: Gas turns acidified potassium manganate (VII) from purple to colourless OR acidified potassium dichromate(VI) from orange to green
Next: Kinetic Particle Theory
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  • Home
  • More Information
  • Contact Me
  • Blog
  • FREE 5-MIN Notes
    • 1. Experimental Techniques
    • 2. Methods of Purification
    • 3. Separation Techniques
    • 4. Qualitative Analysis
    • 5. Kinetic Particle Theory
    • 6. Atomic Structure
    • 7. Elements, Compounds, Mixtures
    • 8. Ionic Bonding
    • 9. Covalent Bonding
    • 10. Mole Concept
    • 11. Electrolysis
    • 12. Energy Changes
    • 13. Speed of Reaction
    • 14. Redox
    • 15. Acids and Bases
    • 16. Salts
    • 17. Ammonia
    • 18. Periodic Table
    • 19. Metals
    • 20. Air
    • 21. Fuels
    • 22. Organic Chemistry
    • 23. Macromolecules
  • Free Printables