How to carry out a flame test
Dip nichrome wire into concentrated HCl and place in the hottest part of a blue flame to clean.
Then dip back into the concentrated HCl and then into the powder.
Place the Wire at the edge of the blue flame and observe the colour change.
Flame Test Colours
Lithium ions produce a scarlet/bright red flame
Sodium ions produce an orange (golden yellow) flame
Potassium ions produce a lilac flame
Calcium ions produce a brick red flame
Barium ions produce an apple green flame
Copper ions produce a blue green flame
Formation of Coloured Precipitates With Sodium Hyd
Calcium - White Precipitate
Aluminium - White Precipitate (Dissolves with excess NaOH)
Magnesium - White precipitate
Copper - Blue/ Green Precipitate
Iron (II) - Sludgy Green
Iron (III) - Rusty Brown
Ammonium - Ammonia gas turns red litmus blue
Tests for Gases
Oxygen - Relights a glowing splint
Carbon Dioxide - turns limewater milky
Hydrogen - Extinguishes a lit splint with a squeeky pop
Chlorine - Bleaches litmus paper white.
Water - Anhydrous (White) copper sulfate turns blue.
Ammonia - Turns red litmus paper blue.
Testing for Carbonate Ions
Add dilute Hydrochloric acid (or any dilute acid)
If carbonate ions are present carbon dioxide will be given off which turns limewater milky.
Testing for Sulfate ions
Add dilute hydrochloric acid, followed by barium chloride solution.
If Sulfate ions are present a white precipitate will form.
Testing for Halide (group 7) ions
Add dilute nitric acid, followed by silver nitrate solution
Chlorine = White Precipitate
Bromine = Cream Precipitate
Iodide = Yellow Precipitate
Testing for Nitrate ions
Warm with sodium hydroxide, followed by aluminium powder.
If nitrate ions are present ammonia gas is given off.
Organic compounds will burn/ char when heated in air
Unsaturated organic compounds will turn orange bromine water colourless