Hydrogen
Lit splint squeaky pop
Oxygen
Glowing splint relights
Carbon dioxide
Turns limewater cloudy
Ammonia
Turns damp red litmus paper blue
Chlorine
Turns damp blue litmus paper red then white
Lithium (flame)
red
Sodium (flame)
yellow
Potassium (flame)
lilac
Calcium (flame)
Brick red
Copper (flame)
blue-green
NH4+
Add sodium hydroxide, heat gently, ammonia gas is given off
Cu2+
Add sodium hydroxide, blue precipitate
Fe2+
Add sodium hydroxide, green precipitate
Fe3+
Add sodium hydroxide, brown precipitate
Cl-
Dilute nitric acid, sliver nitrate, white precipitate
Br-
Dilute nitric acid, silver nitrate, cream precipitate
I-
Dilute nitric acid, silver nitrate, yellow precipitate
SO42- test
Dilute HCl, barium chloride, white precipitate
CO32- test
Dilute HCl, CO2 produced (effervescence)
Water
Anhydrous copper sulphate turns from white to blue
Pure water
Boils at 100°C
Freezes at 0°C
Alkenes
Bromine water goes orange to colourless
Methyl orange indicator
Goes from red to orange in presence of alkaline
Phenolphthalein indicator
Goes from colourless to pink in presence of alkaline