Chemical Tests

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Flame Tests- Metal Ions


1) Place the nichrome wire loop into a solution of HCl and rinse it with distilled water
2) Dip the clean wire loop into a sample of the compund
3) Put the wire loop into the clear blue (hottest) part of the Bunsen flame
4) Clean the loop before placing in other compounds to avoid contamination and incorrect results


Lithium (Li+) gives a crimson flame

Sodium (Na+) gives a yellow flame

Potassium (K+) gives a lilac flame

Calcium (Ca2+) gives a brick red flame

Barium (Ba2+) gives an apple green flame

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Precipitates with NaOH- Metal Ions

1) Add a few drops of NaOH to your metal solution
2) The colour of the insoluble precipitate formed indicates the metal
3) If a white precipitate forms, add excess NaOH and if there is no change, do the flame test


Calcium (Ca2+) produces a white precipitate

Copper(II) (Cu2+) produces a blue precipitate

Iron(II) (Fe2+) produces a green precipitate

Iron(III) (Fe3+) produces a brown precipitate

Aluminium (Al2+) produces a white precipitate, but forms a colourless solution with excess NaOH

Magnesium (Mg2+) produces a white precipitate

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AgNO3 and HNO3- Halide Ions


1) To test for chloride, bromide, or iodide ions, add dilute nitric acid (HNO3), followed by silver nitrate solution (AgNO3)
2) A precipitate will form if one of the above ions is present


A chloride (Cl-) gives a white precipitate of silver chloride

A bromide (Br-) gives a cream precipitate of silver bromide

An iodide (I-) gives a yellow precipitate of silver iodide

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Testing for Carbonates and Sulfate Ions

Carbonates (CO32-):

When carbonates react with acid, they produce carbon dioxide (CO2)

1) Add a dilute acid to the substance and bubble the gas produced through limewater
2) If the limewater turns cloudy, that means that carbon dioxide (CO2) is present. Therefore, a carbonate is present.

Sulfate Ions (SO42-):

1) Add dilute HCl, followed by barium chloride solution (BaCl2)
2) A white precipitate of barium sulfate means the original compound was a sulfate

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