Question

The fusion of an organic compound with solid sodium metal is undertaken for testing nitrogen, sulphur and halogens. This test is called:

• A. Dumas method
• B. Carius method
• C. Kjeldahl's method
• D. Lassaigne's test

Answer 1

The correct option is D Lassaigne's test

It is a general test for the detection of halogens, nitrogen and sulphur in an organic compound. These elements are covalently bonded to the organic compounds. Lassaigne’s test can be carried out only in ionic form. Thus, the elements in a compound are converted from covalent to ionic form by fusing an organic compound with Sodium (Na) metal. The ionic compounds formed during the fusion are extracted in aqueous solution and can be used for detection of halogens, nitrogen and sulphur by simple chemical tests. This called Lassaigne's test.