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Chapter 8 - Reactivity trends III - Qualitative Analysis - Coggle Diagram

- - - - Carbonates react with acids to from carbon dioxide gas
      - Process
        
        In a test tube, add dilute nitric acid to the solid
        
        If you see bubbles, compounds could be a carbonate
        
        Test for CO2
        
        Bubble gas through limewater
        
        CO2 will react with it to form a fine white precipitate of calcium carbonate, which turns the lime water cloudy
  - - - Barium sulfate is very insoluble in water, its a white solid
      - Aqeuous barium sulfate is added to the solution
      - Ba2+ ions are added as aqueous barium chloride/nitrate
      - If you're doing a halide test after, use barium nitrate
    - - Most halides are soluble in water, silver halides are insoluble
      - Aqueous silver ions reaction with aqueous halide ions to from silver halide precipitates
      - Process
        
        Add aqueous silver nitrate, AgNO3 to the solution
        
        Silver halide precipiates are different colours
        
        Silver chloride - white
        
        Silver bromide - cream
        
        Silver iodide - yellow
        
        Add aqueous ammonia, first dilute and then concentrated, to test solubility of the precipiate is useful to tell them apart
        
        Dissolve sample in water
      - Solubillity in ammonia
        
        Dilute
        
        Cl - yes
        
        Br - No
        
        I - No
        
        Concentrated
        
        Cl - Yes
        
        Br - Yes
        
        I - No
- - - - Add dilute acid and looking for effervescence
      - Halides and sulfates don't produce bubbles with dilute acid
      - Test can be done without possibility of incorrect conclusion
      - If no bubbles are produced, move onto next test
    - - Add solution with Ba2+ ions, looking for white precipitate
      - Barium Carbonate is white and insoluble in water
      - Carrying out a sulfate test on a carbonate also produces a white precipitate, so carrying out a carbonate test first ensures it isn't present
    - - Add solution containing Ag+ ions, looking for a precipitate
      - Silver carbonate and silver sulfate are both insoluble and form precipitates
      - Halide test should be last to rule out possibilities of carbonates/ sulphates
  - - - If you see bubbles, continue adding dilute nitric acid until bubbles stop
      - All carbonate ions will then have been removed and there won't be any left to react
      - You must use dilute nitric acid, and sulfuric acid has sulphate ions and HCl has chloride ions which will affect later tests
    - - Add excess barium nitrate to the solution
      - Any sulfate ions present will precipitate
      - Filter solution to remove barium sulfate
    - - To the left over solution, add AgNO3
      - And carbonates present have already been removed, any precipitate formed must have halide ions
      - Add NH3 to confirm which halide you have