Borax bead test : The transparent glassy bead while heated along with inorganic salt and the colour produced gives some idea of cation present in it.
Table:
Colour of bead in oxidising flame
|
Colour of bead in reducing flame
|
Basic radical present
|
Greenish when hot, blue in cold.
|
Red and opaque
|
Cu
|
Dark green in hot and cold
|
Same
|
Cr
|
Deep - blue
|
Deep blue
|
Co
|
Yellow when hot
|
Green
|
Fe
|
Violet in hot and cold
|
Colourless
|
Mn
|
Brown in cold
|
Grey or black or opaque
|
Ni
|