The sodium fusion test, or Lassaigne’s test, is used in elemental analysis for the qualitative determination of the presence of foreign elements, namely halogens. A method of testing for the presence of a halogen, nitrogen, or sulphur in an organic compound. A sample is heated in a test tube with a pellet of sodium. The hot. A drop of ferric chloride is added to this solution. A prussian-blue precipitate of ferric ferrocyanide, Fe4[Fe(CN)6]3 is formed. The formation of the prussian blue.

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The lzssaigne method used involves the following steps. The solid is then treated with alkli again the sulphonamide from the primary amine is filtered OH.

Halogens present in an organic compound lasdaigne sodium halide on fusion with sodium metal. If the Lassaigne’s extract containing excess of sodium metal, sodium cyanide and sulphides are formed instead of sodium thiocyanate. They can be separated by adding sufficient dilute H 2 SO 4 to neutralise the base steam distillation will remove the alcohol. Upon boiling the alkaline iron II salt solution, some iron III ions are insensibly produced by the action of air. On further treating it with ferric chloride, a prussian blue complex, ferricferrocyanide is formed.

A crystalline precipitate indicates the presence of a carbonyl compound. A shining mirror confirms the presence of the aldehyde.

Sodium fusion test – Wikipedia

Physical methods for volatile compounds Victor Meyer’s method: Tes in with your library card. Let the equivalent mass of the acid be E. Not containing N or S soluble in conc. Platinichloride method for bases: Hydrogen is also present in most of the organic compounds, but there are few exceptions, such as: Chemical classification of the amine function: The various methods commonly employed for the estimation of principal elements are discussed lassajgne the table.


Mass of metallic silver. Retrieved 31 Decemberfrom vlab.

Diethyl Ketone and Acetic Acid: Silver salt method for acids: The solution is then filtered and the halide is precipitated with silver nitrate solution. Organic compound containing oxygen is heated with graphite and CO formed is quantitatively converted into CO 2 on reaction with I 2 O 5.

Dibutyl Ether and Chlorobenzene: A mixture of toluene may be separated by extraction with dilute HCl; the aniline passes into the aqueous layer in the form of the salt aniline hydrochloride and may be recovered by neutralization.

Fusion solution is acidified with dil. In Victor Meyer’s method, a known mass of the volatile substance is vaporised in a Victor Meyer’s tube.

Detection of Elements: Lassaigne’s Test (Theory) : Class 11 : Chemistry : Amrita Online Lab

If possible, verify the text with references provided in the foreign-language article. Concentrated H 2 SO 4 dissolves only the dibutyl laxsaigne and it may be recovered from solution by dilution with water. The filtrate is acidified with 2M nitric acid and then test for halogens is performed an mentioned above.

The most commonly occurring elements in organic compounds are carbon, hydrogen, oxygen, nitrogen, ladsaigne and halogen elements. This is converted in to sodium ferrocyanide by the addition of sufficient quantity of ferrous sulphate.

After qualitative analysis of elements, the next step in the determination of molecular formula of an organic compound is the estimation of various elements by mass, i.



The filtrate is acidified with dil. Neutral Ferric Chloride Test: The ionic compounds formed during the fusion are extracted in aqueous solution and can be detected by simple chemical tests. As the addition of chlorine water is continued, the purple colour disappears owing to oxidation of iodine to iodate and if bromine is present, is present, is replaced by a brown or reddish colour. Thus, Equivalent mass of silver salt.

Silver nitrate test a.

Let the volume at NTP be. View a machine-translated version of the Spanish article. From Wikipedia, the free encyclopedia.

Lassaigne’s test

The organic compound containing phosphorus is heated with fuming nitric tsst. Two solutions separately keeped in tightly stoppered bottles and mixed exactly equal volumes immediately before use. Detection of Nitrogen If nitrogen is present in the compound, the Lassaigne’s extract would contain sodium cyanide formed during fusion.

The molecular mass of the organic substance can be calculated by the application of following relationship, Mol. If no colour is observed the test is repeated as above but water substituted by absolute ethanol as lassigne. Test for Nitrogen Cyanide ion and hence nitrogen ion in the sample, may be detected by the Prussian blue test. A Prussian blue precipitate or colouration indicates that nitrogen is present.