Colours of Inorganic Ions and Complexes Flashcards

Flashcards on the colours of inorganic ions and complexes.

MnO4- to Mn2+

Purple to pale pink (practically colourless when dilute) in titrations.

[Cu(H2O)6]2+ from CuSO4.5H2O(s)

Pale blue solid.

Cu(OH)2(s)

Pale blue precipitate.

[Cu(NH3)4(H2O)2]2+ excess NH3 to Cu2+(aq)

Dark blue solution.

CuCl4 2– excess HCl to Cu2+(aq)

Yellow solution.

Cu+ reduction of Cu2+ with I–

White precipitate (CuI) and brown I2.

Cu2+ / Cu Disproportionation of Cu+

Brown solid (Cu) and blue solution (CuSO4).

CoCl4 2– from CoCl2.6H2O(s) plus water and excess HCl

Blue solution.

[Cr(H2O)6]3+ from KCr(SO4)2.12H2O(s)

Pale purple (heat green) solution.

Cr(OH)3(s) NH3 dropwise to Cr 3+(aq)

Dark green precipitate.

[Cr(NH3)6]3+ excess NH3 to Cr 2+(aq)

Purple solution.

[Cr(OH)6]3– excess OH– to Cr(OH)3(s)

Dark green solution.

Cr2O7 2– from K2Cr2O7(s) in 0.1mol dm-3 H2SO4

Orange solution.

CrO4 2– oxidation of Cr3+ with hot alkaline H2O2

Yellow solution.

Fe(OH)2(s) NaOH dropwise to Fe2+(aq)

Dark green precipitate.

[Fe(H2O)6]3+ from FeCl3.6H2O(s)

Yellow solution.

Fe(OH)3(s) NaOH dropwise to Fe3+(aq)

Orange-brown precipitate.

[Mn(H2O)6]2+ from MnSO4.4H2O(s)

Pale pink solution.

Mn(OH)2(s) NaOH dropwise to Mn2+(aq)

Pale brown precipitate.

[Fe(H2O)6]2+ from FeSO4.7H2O(s)

Pale green solution.

MnO4 –/Fe2+ Mn2+/Fe3+

Orange brown (Fe3+) to brown (I2).

I–/Fe3+

I2/Fe2+