A solution thought to contain Fe³⁺ is likely to be (colour). To test for this ion add a few drops of (name of ion) and look for a complex.

Chlorine gas will turn damp (colour) litmus paper (colour) and then it white.
Chlorine will also turn paper blue-black.

To test for the presence of SO₄^2–, first add (name), then (name) solution and look for a (colour) precipitate.

The sulfite ion, SO₃^2– will also form a (colour) precipitate with (name) solution, but this precipitate will in acid.

Iodine is usually (colour) in solution because it forms a with the iodide ion which is often present.
To confirm that iodine is present, add solution and look for a complex.

Coloured redox species you should remember
The ion, MnO₄^–, is .
The manganese(II) ion, Mn²⁺, appears in dilute solution, though it is actually very pale pink.
The ion, Cr₂O₇^2–, is .
The chromium(III) ion, Cr³⁺, is .
, NO₂, is a (colour) acidic gas which is heavier than air.
Copper metal, Cu, is .
The copper(II) ion, Cu²⁺(aq), is . It forms a (colour) complex with (name) solution.