Indicator
H+
|
H2O
|
OH-
|
|
Methyl orange
|
red
|
orange
|
yellow
|
phenolphthalein
|
colourless
|
Pink
|
red
|
Universal indicator
|
red
|
Green
|
blue
|
Common Ion
Fe2+
|
green
|
Cr2O72-
|
orange
|
MnO4-
|
purple
|
Fe3+
|
Yellow brown
|
Cr3+
|
green
|
Mn2+
|
Pale pink/ colourless
|
Cu+
|
green
|
CrO42-
|
yellow
|
MnO-
|
Dark green
|
Cu2+
|
blue
|
MnO-
|
purple
|
||
Ni2+
|
green
|
Mn3+
|
red
|
Common Gas and Liquid
I2
|
brown
|
Br2
|
Yellow brown
|
I2
(in organic solvent)
|
purple
|
Br2
(in organic solvent)
|
orange
|
NO
|
colourless
|
SO2
|
colourless
|
NO2
|
brown
|
||
Transition metal ion
V3+
|
green
|
Sc3+
|
colourless
|
V2+
|
purple
|
Ti3+
|
purple
|
VO2+
|
blue
|
Co2+
|
pink
|
VO2+
|
Yellow
|
||
