Tests for positive ions

Tests for positive ions

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  • Created by: Sam
  • Created on: 16-03-12 17:45

Cation tests

Flame tests

Lithium - Crimson red

Sodium - Yellow

Potassium - lilac

Calcium - Brick red

Barium - Cream

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Test for metal ions with NaOH

Adding NaOH forms a coloured precipitate

Eg. Ca + 2OH       Ca(OH)

Forms white precipitate

Eg. Fe + 3OH        Fe(OH)

Forms reddish brown precipitate

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Ammonium Compounds

Ammonium Compounds

 - add NaOH to compound

 - if Ammonium is present then Ammonia gas is given off (smells)

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Tests for negative ions


Test for CO  using limewater

CO  present water goes cloudy

Also Heat compound and it will decompose to form a coloured precipitate

Copper -  Black

Zinc - Yellow

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Sulfates and Halides


 - add dilute HCL

 - add Barium Chloride

White precipitate of Batrium sulfate forms if Sulfate is present


 - add nitric acid and silver nitrate solution

Chloride - White precipiate of silver chloride

Bromide - Cream precipitate of Silver Bromide

Iodine - yellow Precipitate

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- add aluminium powder to compound

-  add NaOH to compound

If nitrate was present Ammonia is given off

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