IGCSE TESTS REQUIRED TO KNOW FOR YOUR EXAMS
| ANION | TEST | TEST RESULT |
|---|---|---|
|
CHLORIDE
Cl– |
acidify with dilute nitric acid, then add
aqueous silver nitrate |
White precipitate |
|
BROMIDE
Br– |
acidify with dilute nitric acid, then add
aqueous silver nitrate |
Cream precipitate |
|
IODIDE
I– |
acidify with dilute nitric acid, then add
aqueous silver nitrate |
Yellow precipitate |
|
NITRATE
NO3– |
add aqueous sodium hydroxide, then
aluminium foil; warm carefully |
Ammonia produced (it will turn blue a damped ph or red litmus paper |
|
SULFATE SO42– |
acidify, then add aqueous barium nitrate |
white precipitate of BaSO4 |
|
SULFITE SO32– |
add dilute hydrochloric acid, warm gently
and test for the presence of sulfur dioxide |
sulfur dioxide produced will turn acidified aqueous potassium manganate(VII) from purple to colorless |
|
CARBONATE
CO32– |
add dilute acid |
Effervescence, carbon dioxide produced |
| CATION | TEST RESULT WITH NAOH SOLUTION | TEST RESULT WITH AMMONIA SOLUTION |
|---|---|---|
|
COPPER (II)
Cu2+ |
light blue ppt., insoluble in excess |
light blue ppt., soluble in excess, giving a
dark blue solution |
|
IRON(II)
Fe2+ |
green ppt., insoluble in excess |
green ppt., insoluble in excess |
|
IRON(III)
Fe3+ |
red-brown ppt., insoluble in excess |
red-brown ppt., insoluble in excess |
|
CHROMIUM(III)
Cr3+ |
green ppt., soluble in excess |
Content |
|
ZINC
Zn2+ |
white ppt., soluble in excess, giving a
colorless solution |
white ppt., soluble in excess, giving a
colorless solution |
|
CALCIUM
Ca2+ |
white ppt., insoluble in excess |
no precipitate. or very slight white precipitate. |
|
ALUMINUM
Al3+ |
white ppt., soluble in excess, giving a colorless solution |
white ppt., insoluble in excess |
|
AMMONIUM
NH4+ |
ammonia produced on warming |
N/A |
| GAS | TEST | RESULT |
|---|---|---|
|
AMMONIA |
Damped red litmus paper |
Turn blue |
|
CARBON DIOXIDE |
Bubble it through LIME WATER |
Turns Milky |
|
HYDROGEN |
Lighted splint |
POPS |
|
OXYGEN |
Glowing splint |
relights |
|
CHLORINE |
pH paper or litmus paper (any color) |
bleaches them |
|
SULFUR DIOXIDE |
Acidified aqueous potassium manganate (VII)
(also called potassium permanganate) |
Change from purple to colorless |
| Gas | Symbol | ||
| Carbon dioxide | bubble gas through limewater (calcium hydroxide solution) | Turns limewater cloudy.
| |
| Hydrogen | Put a lighted splint into a sample of the gas. | Burns with a “popping” sound
| |
| Oxygen | Put a glowing splint into a sample of the gas. | Splint relights.
| |
| Chlorine | Put a damp BLUE litmus paper, it will get red first and then bleach immediately.
| Splint relights. | |
| Ammonia | Put a damp RED litmus paper and it will TURN BLUE. | Splint relights. |