AG Tests for Anions Chloride Sulfate/sulfite carbonate/hydrogen carbonate nitrate phosphate (NB know...
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Transcript of AG Tests for Anions Chloride Sulfate/sulfite carbonate/hydrogen carbonate nitrate phosphate (NB know...
AG
Tests for Anions
• Chloride
• Sulfate/sulfite
• carbonate/hydrogen carbonate
• nitrate
• phosphate
• (NB know confirmatory test too!)
AG
Chloride
• Add
AgNO3
• Getwhite ppt
• Confirm = ppt dissolves in dilute ammonia
• Equation needed
AG
Sulfate/sulfite
• Add
BaCl2• Get
white ppt• Distinguish • add
dil HCl to white ppt• ppt remains = sulfate• ppt dissolves = sulfite
Equation needed !!
AG
CO32- /HCO3
-
• Adddil. HCl (or any acid)
• Get bubbles of CO2 (limewater milky)
• Distinguish• add
MgSO4 to fresh solution• Get
white ppt. immediately = carbonatewhite ppt on heating = hydrogen carbonateEquation needed !!
AG
Nitrate
• Brown Ring Test• Add
fresh FeSO4
At slant add conc. H2SO4 drop wise• Get
brown ring at junction of 2 layers
No equation needed
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Phosphate
• Addammonium molybdate
• Add 5 drops of conc. nitric acid (warm the solution)
• Get yellow ppt
No equation needed
Confirm: Goes colourless when add dilute NH3
AG
Questions
• You add ammonium molybdate when testing for ?• Phosphates• You add silver nitrate when testing for ?• Chlorides• You use Magnesium sulfate for?• Distinguishing between carbonates and
hydrogencarbonates • (white ppt formed immediately means carbonate)
AG
Questions
• BaCl2 is used to test for which two anions?• Sulfates and sulfites• You add conc.nitric acid when testing for ?• phosphates• You add dilute HCl in which 4 anion tests• Gives CO2 with both carbonates and hydrogencarbonates• As distinguishing test for sulfates and sulfites – both gave white
ppt with BaCl2• (sulfate – ppt unchanged)
AG
Questions
• AgNO3 is used to test for ?• Chloride• You add conclusion can you draw if a white ppt
forms when BaCl2 is added to a solution ?• Solution is either a sulfate or sulfite• What is the confirmatory test for phosphates?• The yellow ppt(from addition of ammonium molybdate, conc HNO3 and gentle heating ) dissolves in
dilute ammonia solution (NH4OH)