Chemistry Revision
Chemical Tests
Cations Add NaOH solution Add Ammonia Solution
Cu2+ Blue PPT Blue PPT
Excess: No change Excess: No change
Fe2+ Green PPT Green PPT
Excess: No change Excess: No change
Fe3+ Red-brown PPT Red-brown PPT
Excess: No change Excess: No change
NH4 2+ Pungent Gas is produced No Change
-> Tested by damp red litmus -> Same substance does not react
paper turns blue
Zn+ White PPT White PPT
Excess: Dissolved Excess: Dissolved
Ca+ White PPT White PPT
Excess: No change Excess: No change
Al+ White PPT White PPT
Excess: Dissolved Excess: No change
Anions Test Result
Cl- Add dilute nitric acid + silver White PPT
nitrate solution
Br- Add dilute nitric acid + silver Cream PPT
nitrate solution
I- Add dilute nitric acid + silver Yellow PPT
nitrate solution
So4 2- Add dilute HCL + barium White PPT
chloride solution
SO3 2- Add dilute HCL Fizzing
Gas is tested by acidified Orange to Green
potassium chromate VI
CO3 2- Add dilute HCL Fizzing
Gas is tested by limewater Limewater turns milky
NO3- Add NaOH solution and Pungent Gas is produced and
ammonium power. litmus paper turns blue
Gas is tested by red damp
litmus paper
Gas Preparations
1) Oxygen (O2)
- Reactant: Hydrogen Peroxide (H2O2)
- Catalyst: Manganese IV Oxide (MnO2)
- Equation: 2H2O2 -> 2H2O + O2
- Method of collection: Over water -> not soluble
- Test: Glowing Splint relights itself
- Use: Breathing Aid
2) Hydrogen (H2)
- Equation: Metal + Acid -> Salt + Hydrogen
- Method of collection:
o Over water -> not soluble
o Upward Delivery Method -> Less dense than air
- Test: Lighted splint makes a pop sound
- Use: Rocket Fuel
3) Carbon Dioxide (CO2)
- Equation: Metal Carbonate + Acid -> Salt + Carbon Dioxide + Water
- Method of collection: Downward Delivery Method -> Denser than air
- Test: Limewater turns milky
- Use: Fire Extinguishers
4) Ammonia (NH4)
- Equation: Ammonium Salt + Alkali -> Salt + Water + Ammonia
- Method of collection: Upward delivery method -> Less dense than air
- Test: Damp red litmus paper turns blue
- Use: Fertilisers
5) Chlorine (Cl2)
- Equation: MnO2 + 4HCl -> MnCl2 + 2H2O + Cl2
- Method of collection: Downward Delivery Method -> Denser than air
- Test: Damp red litmus paper turns white
- Use: Swimming Pools
6) Sulfur Dioxide (SO2)
- Equation: Sodium Sulfite (NaSO3) + Sulfuric Acid (H2SO4) -> Na2SO4 + H2O + SO2
- Method of Collection: Downward Delivery Method -> Denser than air
- Test: Acidified Potassium Chromate VI turns orange to green
- Use: H2SO4 manufacture
