SOS Chemistry Tables
Flame Tests for Metal Cations
Cation Flame Colour
Magnesium ion Blinding White
Barium ion Apple Green
Copper ion Green Blue
Calcium ion Brick Red
Sodium ion Yellow Orange
Potassium ion Lilac
Sodium Hydroxide Test for Metal Cations
Aluminium Al3+ White *
Calcium Ca2+ White *
Magnesium Mg2+ White *
Copper Cu2+ Blue
Iron Fe2+ Green
Iron Fe3+ Brown (rust)
*If you get a white precipitate, add more sodium hydroxide solution and the aluminium
precipitate will dissolve. If the white precipitate does not dissolve then the metal ion is
calcium or magnesium. These can be distinguished using a flame test (magnesium ions
have no flame colour).
Silver Nitrate Test for Halide Anions
*You first add a few drops of dilute Nitric acid (HNO3) to clear impurities and then a few
drops of Silver Nitrate solution (AgNO3) to create a precipitate to identify the ion.
Halide Anion Colour of Precipitate
Test for aqueous Sulfate ions (SO4
To identify Sulfate ions we first add drops of hydrochloric acid to the sample and
then add a few drops of Barium Chloride. If Sulfate ions are present in the solution then a
white precipitate of insoluble Barium Sulfate will form.
(aq) → BaSO4 (s)
Test for Carbonate ions (CO3
When hydrochloric acid or nitric acid is added to any carbonate containing
compound, either solid or in solution, Carbon Dioxide is given off, which if bubbled through
limewater it turns limewater milky.
(aq) → CO2(g) +H2O(l)
Test for Ammonium ions (NH4
To test for ammonium ions, you first add to the sample few drops of the reagent
sodium hydroxide solution, then you warm the sample, and if Ammonium ions are present, a
distinctive pungent smell is given off while damp red litmus paper turns blue.
(aq) + OH-
→ NH3 + H2O
Hydroxide ions (from
the sodium hydroxide
Test for gases
Hydrogen: You hold a lighted splint in the mouth of the test tube and if hydrogen gas is
present it will explode with a ‘squeaky’ pop.
Oxygen: You hold a glowing splint in the mouth of the test tube and if oxygen gas is present
the splint will relight.
Carbon Dioxide:When bubbled through limewater, limewater turns milky.
Chlorine: It is very toxic. It turns damp blue litmus paper red and later white as it is
Test for starch
Add Iodine reagent to a solution or directly on a potato or other materials
such as bread, crackers, or flour. A blue-black color results if starch is present.
Halogen State at room
Characteristics M.P. Reactivity
Fluorine Gas Pale Yellow Increases
Chlorine Gas Yellow-Green
Bromine Liquid Liquid: Red-Brown
Iodine Solid Solid: Grey;
Gas: (Sublimation) Violet
All nitrates None
Most sulfates Lead sulfate, barium sulfate and calcium sulfate
Most chlorides, bromides and
Silver chloride, silver bromide, silver iodide, lead
chloride, lead bromide, lead iodide
Most other carbonates
Most other hydroxides