Beilstein test or copper wire test  - Halogens

A clean copper wire is heated in the Bunsen flame till it does not impart any type of green colour to the flame. The heated side is dipped within the organic compound and heated again. The presence of a green or bluish green flame because of the formation of volatile cupric halides points out the presence of some halogen in the organic element. Even this test is very sensitive yet it does not confirm the existence of halogens in an organic compound as certain organic compounds such as urea, thiourea, pyridine, organic acids etc. which do not consist of halogens give this test because of the formation of volatile cupric cyanide. It doesn't tell as to which halogen is exist.