Reactions and Colours Flashcards
Cr 6+
Orange
Cr 3+
Green
Cr 2+
Blue
Cr2O7 2-
Orange
CrO4 2-
Yellow
MnO4 -
Purple
Mn 2+
Pink
Fe 2+
Green
Fe 3+
Pale violet
[Fe(H2O)6] 2+
Pale green
[Fe(H2O)6] 2+ with NaOH
Green gelatinous ppt of Fe(H2O)4(OH)2
-Soon oxidised by air to brown [Fe(H2O)3(OH)3]-
[Fe(H2O)6] 2+ with excess NaOH
No change
Green gelatinous ppt of Fe(H2O)4(OH)2
-Soon oxidised by air to brown [Fe(H2O)3(OH)3]-
[Fe(H2O)6] 2+ with NH3
Green gelatinous ppt of Fe(H2O)4(OH)2
-Soon oxidised by air to brown [Fe(H2O)3(OH)3]-
[Fe(H2O)6] 2+ with excess NH3
No change
Green gelatinous ppt of Fe(H2O)4(OH)2
-Soon oxidised by air to brown [Fe(H2O)3(OH)3]-
[Fe(H2O)6] 2+ with Na2CO3
Green precipitate of FeCO3
[Co(H2O)6] 2+
Pink
[Co(H2O)6] 2+ with NH3
Blue ppt of CO(H2O)4(OH)2
[Co(H2O)6] 2+ with excess NH3
Pale yellow-brown sol of [Co(NH3)6]2+
- Oxidised by air to dark brown mixture containing Co(II) compounds.
- A blue ppt is formed as an intermediate
[Co(H2O)6] 2+ with Na2CO3
Pink ppt of CoCO3
[Co(H2O)6] 2+ with HCl
Dark blue sol of [CoCl4]2-
[Cu(H2O)6] 2+
Pale blue
[Cu(H2O)6] 2+with NaOH
Pale blue ppt of Cu(H2O)4(OH)2
[Cu(H2O)6] 2+ with excess NaOH
No change
Pale blue ppt of Cu(H2O)4(OH)2
[Cu(H2O)6] 2+ with NH3
Pale blue ppt of Cu(H2O)4(OH)2
[Cu(H2O)6] 2+ with excess NH3
Deep blue ppt of [Cu(NH3)4(H2O)2]2+
[Cu(H2O)6] 2+ with Na2CO3
Blue-green ppt of CuCO3
[Cu(H2O)6] 2+ with HCl
Yellow sol of [CuCl4]2-
-Likely to appear green as some blue [Cu(H2O)6)]2- will remain.
[Fe(H2O)6] 3+
Purple/yellow/brown
[Fe(H2O)6] 3+ with NaOH
Brown gelatinous ppt of Fe(H2O)3(OH)3
[Fe(H2O)6] 3+ with excess NaOH
No change
Brown gelatinous ppt of Fe(H2O)3(OH)3
[Fe(H2O)6] 3+ with NH3
Brown gelatinous ppt of Fe(H2O)3(OH)3
[Fe(H2O)6] 3+ with excess NH3
No change
Brown gelatinous ppt of Fe(H2O)3(OH)3
[Fe(H2O)6] 3+ with Na2CO3
Brown gelatinous ppt of [Fe(H2O)3(OH)3] with bubbles of CO2
[Al(H2O)6] 3+
Colourless
[Al(H2O)6] 3+ with NaOH
White ppt of Al(H2O)3(OH)3
[Al(H2O)6] 3+ with excess NaOH
Colourless sol of [Al(OH)4]-
[Al(H2O)6] 3+ with NH3
White ppt of Al(H2O)3(OH)3
[Al(H2O)6] 3+ with excess NH3
No change
White ppt of Al(H2O)3(OH)3
[Al(H2O)6] 3+ with Na2CO3
White ppt of [Al(H2O)3(OH)3] with bubbles of CO2
[Cr(H2O)6] 3+
Violet/ruby
[Cr(H2O)6] 3+ with NaOH
Green ppt of Cr(H2O)3(OH)3
[Cr(H2O)6] 3+ with excess NaOH
Green sol of [Cr(OH)6]3-
[Cr(H2O)6] 3+ with NH3
Green ppt of Cr(H2O)3(OH)3
[Cr(H2O)6] 3+ with excess NH3
Purple sol of [Cr(NH3)6]3+
-A green ppt is formed as an intermediate
[Cr(H2O)6] 3+ with Na2CO3
Green ppt of Cr(OH)3 + with bubbles of CO2
