Q. Which of the following radicals, gives the apple green flame during flame test?
AMUAMU 2004
Solution:
Flame colouration All the alkali and some alkaline metals impart a characteristic colour to the flame. When paste of salt in conc. $HCl$ is burnt on a spetchula the following coloured flame appears for different radicals.
Cation
Colour
$Na ^{+}$
golden yellow
$K ^{+}$
violet
$Ca ^{2+}$
brick red
$Sr ^{2+}$
crimson red
$Ba ^{2+}$
apple green
Therefore $Ba ^{2+}$ radical gives the apple green flame during flame test.
| Cation | Colour |
|---|---|
| $Na ^{+}$ | golden yellow |
| $K ^{+}$ | violet |
| $Ca ^{2+}$ | brick red |
| $Sr ^{2+}$ | crimson red |
| $Ba ^{2+}$ | apple green |