Chemistry: Experimental Techniques and Chemical Analysis

Observing dark green crystals ndicates

It contain Ni2+ ions

Observing yellow-brown crystals indicates

It contains Fe3+ ions

Calcium flame colour:

Orange-red

Testing aqueous cations (With NaOH): Precipitate is soluble in excess, giving a colourless solution, Precipitate: White

Cation: Al2+, Zn+

Testing aqueous cations (With NaOH): Precipitate is insoluble in excess, Precipitate: Green

Cation: Cr3+

Testing aqueous cations (With NaOH): Precipitate is insoluble in excess, turns brown near the surface on standing, Precipitate: Green

Cation: Fe2+

Testing aqueous cations (With NH3 solution): Precipitate is insoluble in excess, Precipitate: White

Cation: Al3+

Testing aqueous cations (With NH3 solution): No change, Precipitate: No precipitate or very slight white precipitate

Cation: Ca2+

Test for aqueous anions: Test: Add dil. acid, Result: Effervescence (CO2)

Anion: Carbonate

Test for aqueous anions: Test: Add aq. Sodium Hydroxide, then Alumninium foil and warm carefully, Result: Ammonia gas

Anion: Nitrate

Test for aqueous anions: Test: Acidify, then add aq Barium Nitrate/Barium Chloride, Result: White precipitate

Anion: Sulphate

Observing black powder indicates

Carbon, O2- or S2- ions in an ionic compound

Observing pale green crystals indicates

It contains Fe2+ ions

Observing blue/blue-green crystals indicates

It contains Cu2+ ions

The smell of Ammonia indicates

It contains NH4+ ions

Lithium flame colour:

Red

Sodium flame colour:

Yellow

Potassium flame colour:

Lilac

Barium flame colour:

Light green

Copper (CU2+) flame colour:

Blue-green

Testing aqueous cations (With NaOH): Precipitate is insoluble in excess, Precipitate: White

Cation: Ca2+

Testing aqueous cations (With NaOH): Precipitate is insoluble in excess, Precipitate: Light blue

Cation: Cu2+

Testing aqueous cations (With NaOH):Precipitate is insoluble in excess, Precipitate: Red-brown

Cation: Fe3+

Testing aqueous cations (With NH3 solution): Precipitate insoluble in excess, Precipitate: Green

Cation: Cr3+

Testing aqueous cations (With NH3 solution): Precipitate is soluble in excess, giving a dark-blue solution, Precipitate: Light blue

Cation: Cu2+

Testing aqueous cations (With NH3 solution): Precipitate is insoluble in excess, turns brown near the surface of standing, Precipitate: Green

Cation: Fe2+

Testing aqueous cations (With NH3 solution): Precipitate is insoluble in excess, Precipitate: Red-brown

Cation: Fe3+

Testing aqueous cations (With NH3 solution): Precipitate is soluble in excess, giving a colourless solution, Precipitate: White

Cation: Zn2+

Test for aqueous anions: Test: Acidify with dil. Nitric acid, then add aq. Silver Nitrate, Result: White precipitate

Anion: Chloride

Test for aqueous anions: Test: Acidify with dil. Nitric acid, then add aq. Silver Nitrate, Result: Cream precipitate

Anion: Bromide

Test for aqueous anions: Test: Acidify with dil. Nitric acid, then add aq. Silver Nitrate, Result: Yellow precipitate

Anion: Iodide

Test for aqueous anions: Test: Add small vol. of acidified aq. Potassium Manganate (VIII), Result: Acidified aq. Potassium Manganate (VIII) changes colour from purple to colourless

Anion: Sulphite

'Pops' in the presence of a lighted splint

Hydrogen

Relights a glowing splint

Oxygen

Turns limewater a cloudy white

Carbon Dioxide

Turns damp red litmus blue

Ammonia

Turns acidified potassium dichromate (VI) from orange to green
Turns acidified potassium manganate (VIII) from purple to colourless

Sulfur Dioxide

Bleaches damp litmus paper

Chlorine

Observing dark green crystals ndicates

It contain Ni2+ ions

Observing yellow-brown crystals indicates

It contains Fe3+ ions

Calcium flame colour:

Orange-red

Testing aqueous cations (With NaOH): Precipitate is soluble in excess, giving a colourless solution, Precipitate: White

Cation: Al2+, Zn+

Testing aqueous cations (With NaOH): Precipitate is insoluble in excess, Precipitate: Green

Cation: Cr3+

Testing aqueous cations (With NaOH): Precipitate is insoluble in excess, turns brown near the surface on standing, Precipitate: Green

Cation: Fe2+

Testing aqueous cations (With NH3 solution): Precipitate is insoluble in excess, Precipitate: White

Cation: Al3+

Testing aqueous cations (With NH3 solution): No change, Precipitate: No precipitate or very slight white precipitate

Cation: Ca2+

Test for aqueous anions: Test: Add dil. acid, Result: Effervescence (CO2)

Anion: Carbonate

Test for aqueous anions: Test: Add aq. Sodium Hydroxide, then Alumninium foil and warm carefully, Result: Ammonia gas

Anion: Nitrate

Test for aqueous anions: Test: Acidify, then add aq Barium Nitrate/Barium Chloride, Result: White precipitate

Anion: Sulphate

Observing black powder indicates

Carbon, O2- or S2- ions in an ionic compound

Observing pale green crystals indicates

It contains Fe2+ ions

Observing blue/blue-green crystals indicates

It contains Cu2+ ions

The smell of Ammonia indicates

It contains NH4+ ions

Lithium flame colour:

Red

Sodium flame colour:

Yellow

Potassium flame colour:

Lilac

Barium flame colour:

Light green

Copper (CU2+) flame colour:

Blue-green

Testing aqueous cations (With NaOH): Precipitate is insoluble in excess, Precipitate: White

Cation: Ca2+

Testing aqueous cations (With NaOH): Precipitate is insoluble in excess, Precipitate: Light blue

Cation: Cu2+

Testing aqueous cations (With NaOH):Precipitate is insoluble in excess, Precipitate: Red-brown

Cation: Fe3+

Testing aqueous cations (With NH3 solution): Precipitate insoluble in excess, Precipitate: Green

Cation: Cr3+

Testing aqueous cations (With NH3 solution): Precipitate is soluble in excess, giving a dark-blue solution, Precipitate: Light blue

Cation: Cu2+

Testing aqueous cations (With NH3 solution): Precipitate is insoluble in excess, turns brown near the surface of standing, Precipitate: Green

Cation: Fe2+

Testing aqueous cations (With NH3 solution): Precipitate is insoluble in excess, Precipitate: Red-brown

Cation: Fe3+

Testing aqueous cations (With NH3 solution): Precipitate is soluble in excess, giving a colourless solution, Precipitate: White

Cation: Zn2+

Test for aqueous anions: Test: Acidify with dil. Nitric acid, then add aq. Silver Nitrate, Result: White precipitate

Anion: Chloride

Test for aqueous anions: Test: Acidify with dil. Nitric acid, then add aq. Silver Nitrate, Result: Cream precipitate

Anion: Bromide

Test for aqueous anions: Test: Acidify with dil. Nitric acid, then add aq. Silver Nitrate, Result: Yellow precipitate

Anion: Iodide

Test for aqueous anions: Test: Add small vol. of acidified aq. Potassium Manganate (VIII), Result: Acidified aq. Potassium Manganate (VIII) changes colour from purple to colourless

Anion: Sulphite

'Pops' in the presence of a lighted splint

Hydrogen

Relights a glowing splint

Oxygen

Turns limewater a cloudy white

Carbon Dioxide

Turns damp red litmus blue

Ammonia

Turns acidified potassium dichromate (VI) from orange to green
Turns acidified potassium manganate (VIII) from purple to colourless

Sulfur Dioxide

Bleaches damp litmus paper

Chlorine