Testing for Cations

I form a pale blue precipitate in NaOH.

• iron(II) ions

• copper(II) ions

• iron(III) ions

• nickel(II) ions

• manganese(II) ions

I form a green precipitate in NaOH which turns brown on standing.

• iron(II) ions

• copper(II) ions

• iron(III) ions

• nickel(II) ions

• manganese(II) ions

I form a cream precipitate in NaOH which turns brown on standing.

• iron(II) ions

• copper(II) ions

• iron(III) ions

• nickel(II) ions

• manganese(II) ions

Group 1 cations and ammonium form...

• a white precipitate

• a cream precipitate

• a grey-green precipitate

• no precipitate

Magnesium, calcium, strontium and barium ions all form white precipitates which do not dissolve in XS NaOH. How can they be distinguished?

• Flame Test

• Litmus Test

• Universal indicator paper

• Reaction with aq. ammonia

Zinc(II) and aluminium(II) ions can be distinguished by using aq. ammonia.

• True

• False

Calcium, barium and strontium ions form strong white precipitates with aq. ammonia.

• True

• False

Copper(II) ions form a complex ion in XS aq. ammonia, which forms a deep blue precipitate.

• True

• False