Question

An organic compound which produces a bluish-green flame when heated on a copper wire is:

• A. benzaldehyde
• B. aniline
• C. chlorobenzene
• D. benzoic acid

Answer 1

Answer: (C)

chlorobenzene

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 defect the presence of halogen in an organic compound. Green colour of the flame is due to formation of copper halide. The test does not detect fluorine/fluorides.
The sodium fusion test can also be used. Organic material is converted to inorganic salts which include the sodium halide. Silver nitrate solution is added to precipitate halides as the respective silver halide.