anion tests
DESCRIPTION
Anion tests. Common ions. Cl -. Chloride. Carbonate. CO 3 - -. Hydrogen Carbonate. HCO 3 -. Sulfate. SO 4 - -. SO 3 - -. Sulfite. NO 3 -. Nitrate. PO 4 - - -. Phosphate. Chloride test. Make a solution of the salt Add silver nitrate solution If chloride it produces…… - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/1.jpg)
Anion tests
![Page 2: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/2.jpg)
Common ions
Chloride Cl-
Carbonate CO3- -
Hydrogen Carbonate HCO3-
Sulfate SO4- -
Sulfite SO3- -
Nitrate NO3-
Phosphate PO4- - -
![Page 3: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/3.jpg)
Chloride test
• Make a solution of the salt
• Add silver nitrate solution
• If chloride it produces……
• A white precipitate
AgNO3 + NaCl = AgCl + NaNO3
+ - + -
![Page 4: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/4.jpg)
Confirm chloride
• Take the white precipitate obtained earlier
• Add….
• Ammonia solution
• If chloride….
• The precipitate dissolves
![Page 5: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/5.jpg)
Nitrate
• ‘Brown ring test’• Make a solution of the salt• Add Iron sulfate solution• Mix• Add conc sulfuric acid • This sinks to the bottom• A brown ring forms • At the top of the sulfuric acid layer
![Page 6: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/6.jpg)
Phosphate
• Make a solution of the salt
• Add
• Ammonium molybdate solution
• Add….
• Conc nitric acid
• If phosphate a
• Yellow precipitate forms
![Page 7: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/7.jpg)
Sulfate or sulfite
• Make a solution of the salt
• Add barium chloride solution
• both sulfate and sulfite give…..
• A white precipitate
BaCl2+ Na2SO4
= BaSO4+ NaCl
++ - + - - ++ - - + -
BaCl2 + Na2SO3= BaSO3
+ NaCl
![Page 8: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/8.jpg)
Distinguish Sulfate or sulfite
BaSO3 + HCl = BaCl2 + H2O
• Take the white precipitate obtained earlier
• Add dilute hydrochloric acid
• If the precipitate dissolves
• the salt was…
• Sulfite
• If it does not dissolve it is sulfate
SO2+
BaSO4+ HCl =
No reaction
![Page 9: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/9.jpg)
Distinguish between sulfate and sulfite
• Take the white precipitate obtained earlier
• Add dilute hydrochloric acid
• If the precipitate dissolves
• the salt was…
• Sulfite
• If it does not dissolve it is sulfate
![Page 10: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/10.jpg)
Carbonate or HydrogenCarbonate
• Add hydrochloric acid to the solid
• Check for carbon dioxide gas using
• Lime water
• If it turns
• Milky
• It indicates the presence of carbonate or hydrogen carbonate
![Page 11: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/11.jpg)
Solubility of CO3- - and HCO3
-
Carbonates are generally insoluble
Hydrogen carbonates are generally soluble
Except Sodium carbonate Na2CO3
![Page 12: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/12.jpg)
Distinguish between carbonate and hydrogencarbonate
• Make a solution of the salt
• Add a magnesium sulfate solution
• If you get a white precipitate it indicates
• Carbonate
• If no precipitate it indicates
• It indicates Hydrogen carbonate
MgSO4+ Na2CO3 = MgCO3
Na2SO4+
++ +++ +- - - - - - - -
![Page 13: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/13.jpg)
Distinguish between carbonate and hydrogencarbonate
• Make a solution of the salt
• Add a magnesium sulfate solution
• If you get a white precipitate it indicates
• Carbonate
• If no precipitate it indicates
• It indicates Hydrogen carbonate
MgSO4+ NaHCO3 = MgHCO3
Na2SO4+
++ +++ +- - - - - - -
![Page 14: Anion tests](https://reader036.vdocuments.mx/reader036/viewer/2022062301/56815104550346895dbf2389/html5/thumbnails/14.jpg)
Confirm hydrogencaronate
• Boil the clear solution obtained
• If it is a Hydrogencarbonate…..
• A white precipitate now forms