Flame Coloration by Alkali and Earthalkali Metal Compounds
Hydrochloric acid, c = 1 mol/L - WARNING
Lithium chloride - WARNING
H302, H315, H319
|Sodium chloride||Not a dangerous substance according to GHS|
|Potassium chloride||Not a dangerous substance according to GHS|
Calcium chloride - WARNING
Strontium chloride - DANGER
H315, H318, H335
|Barium sulfate||Not a dangerous substance according to GHS|
For each of the following samples a magnesia rod is dipped into diluted hydrochloric acid and held into a burner flame until there is no visible flame coloration. The magnesia rod is then coated with diluted hydrochlorid acid and a sample of one of the following salts is applied to it: lithium chloride, sodium chloride and potassium chloride as well as calcium chloride, strontium chloride and barium sulfate. The rod with the sample is then held into the flame of a gas burner.
The flame takes on a characteristic color, starting with carmine red (lithium, strontium), then yellow (sodium), orange (calcium) and green (barium) up to violet (potassium). Especially the violet color from potassium salts can be observed far better viewing it through a cobalt glass.