IGCSE Double Chemistry Chemical Tests

Ammonium NH4+

NaOH test; litmus paper turns blue

Copper Cu2+

NaOH test; blue precipitate

Iron (II) Fe2+

NaOH test; green precipitate

Iron (III) Fe3+

NaOH test; orange-brown precipitate

Chloride Cl-

Add nitric acid and silver nitrate; white precipitate

Bromide Br-

Add nitric acid and silver nitrate; cream precipitate

Iodide I-

Add nitric acid and silver nitrate; yellow precipitate

Sulphate (SO4 2-)

Add barium chloride and hydrochloric acid

Carbonate (CO3 2-)

Add dilute hydrochloric acid and bubble through limewater; cloudy/milky result

Sodium Na+

Flame test; yellow

Lithium Li+

Flame test; red

Potassium K+

Flame test; lilac

Copper Cu2+

Flame test; green

Calcium Ca2+

Flame test; orange-red flame

Hydrogen H2

Test with lighted splint — produce pop sound

Oxygen O2

Test with glowing splint — splint relights

Chlorine Cl2

Test with wet litmus paper — litmus paper bleached white

Ammonia NH3

Test with wet litmus paper — turns blue

Carbon Dioxide CO2

Bubble through limewater — limewater turns cloudy/milky

Test for H2O

Add anhydrous copper sulphate — turns from white to blue