Hi, Renee. If you heat an ionic salt in a clear or light blue burner flame, some of them (including
potassium) show a characteristic color to the eye (all of them give unique colors if you look
through a spectroscope). In the case of potassium, the color is lavender.
However: you need to have a CLEAN wire loop (platinum or nickel-chromium most common)
and a way to hold it (not your fingers, please) in the flame. Wash the loop in concentrated
hydrochloric acid (caution--nasty stuff, wear safety equipment) and rinse in distilled or
de-ionized water. Put the loop in the hot part of the burner flame. If there is a burst of color, the
wire is not clean enough (clean it again). When the wire loop is clean, heat it and touch a bit of
your unknown. This should transfer enough to the loop to carry out the flame test. If it doesn't,
make a few drops of saturated solution using the unknown in distilled water.
The main difficulty is getting the wire clean enough. Sodium ion (yellow flame test)is much
brighter than potassium and is a common contaminant. A little bit of sodium will mask a lot of
Look in the Handbook of Chemistry and Physics for a list of flame test colors. You may also
want to look into a process called the "borax bead" test. Have fun!
Author: Garcia Oliver firstname.lastname@example.org