Colour of Inorganic Ions

What color does MnO4– turn to in titrations?

It changes to pale pink (Mn2+).

What color is [Cu(H2O)6]2+ from CuSO4.5H2O?

Pale blue.

What happens when NH3 is added dropwise to Cu2+?

A pale blue precipitate forms.

What color does [Cu(NH3)4(H2O)2]2+ appear with excess NH3?

Dark blue.

What color does CuCl42– turn with excess HCl?

Yellow.

What is the result of reducing Cu2+ with I–?

White precipitate (CuI) and brown I2.

What occurs during the disproportionation of Cu+?

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

What color is CoCl42– from CoCl2.6H2O plus water and excess HCl?

Blue.

What color does [Cr(H2O)6]3+ appear from KCr(SO4)2.12H2O?

Pale purple, often green due to impurities.

What happens when NH3 is added dropwise to Cr3+?

A dark green precipitate forms.

What color is [Cr(NH3)6]3+ with excess NH3?

Purple.

What color does [Cr(OH)6]3– turn with excess OH–?

Dark green.

What color is Cr2O72– from K2Cr2O7 in 0.1mol dm-3 H2SO4?

Orange.

What color does CrO42– turn during oxidation of Cr3+ with hot alkaline H2O2?

Yellow.

What color is Fe(OH)2 when NaOH is added dropwise to Fe2+?

Dark green precipitate.

What color is [Fe(H2O)6]3+ from FeCl3.6H2O?

Yellow.

What color does Fe(OH)3 form with NaOH added to Fe3+?

Orange-brown precipitate.

What color is [Mn(H2O)6]2+ from MnSO4.4H2O?

Pale pink.

What color does Mn(OH)2 turn with NaOH added to Mn2+?

Pale brown precipitate.

What color is [Fe(H2O)6]2+ from FeSO4.7H2O?

Pale green.

What color change occurs from MnO4–/Fe2+ to Mn2+/Fe3+?

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

What color change occurs from I–/Fe3+ to I2/Fe2+?

Brown to colorless.