Question

An organic compound which produces a bluish green flame when heated on copper wire is?
A.Benzaldehyde
B.Aniline
C.Chlorobenzene
D.Benzoic acid

Answer 1

Hint: For solving this we need to know about the test which is required to detect the presence of halogens in organic compounds. Beilstein is one of the tests which is used for this.

Complete step by step answer:
An organic compound which produces a bluish green flame when heated on a copper wire is chlorobenzene. This is called Beilstein's test and this test is used to detect the presence of halogen in an organic compound. Green colour of the flame is due to the formation of copper halide. The test does not detect fluorine/fluorides.
This test is a simple chemical test for organic halides. It was developed by Friedrich Konrad Beilstein. In this test a copper wire is cleaned and is heated in a Bunsen burner flame to form a coating of copper oxide over it. Then it is dipped in the sample which is to be tested and is heated again in a flame. A positive test is indicated by a green flame caused by the formation of a copper halide.


The sodium fusion test can also be used instead of Beilstein’s test. Organic material is converted to inorganic salts which include the sodium halide and then silver nitrate solution is added to precipitate halides as the respective silver halide.


So, the correct answer is Option C .

Additional Information:
Additional Data (in points)

Note:
The test does not detect fluorine/fluorides. This test is no longer frequently used. One of the reasons why it is not widely used is because it possibly generates highly toxic chloro-dioxins if the test material is a polychloroprene which is injurious to health.