salt05 Beilstein Test for halogen compounds

* Take 10 cm of a copper wire (O 0.6 mm) insulated by PVC, remove half of the insulation and bend a loop .
* Lit your micro burner and hold the loop into the upper part of its flame.
* Press the glowing loop into a piece of PVC insulation and repeat heating.
Observations left: The blue colour turns yellow. Right: A green colour can be seen.
* Green colour also appears when glowing copper was in contact with hydrochloric and other acids of experiment 3. No colour change is observed using other samples of plastic (i.e. from molecule models).
Explanation: Fluorine, chlorine and bromine atoms from PVC or from halogen hydrogen acids react with copper resulting in volatile copper halogenides which produce a green flame colour.