Why potassium metal Cannot be used for fusion test instead of sodium?

Halogens form sodium halide by fusion with sodium metal in an organic compound. Potassium can, technically, be used in place of sodium. However, since the experiments are conducted in an aqueous solution, the explosive reaction during the application of potassium is difficult to monitor.

What is the purpose of making sodium extract for the detection of foreign element?

The content is grinded and then filtered. Thus, obtained filtrate is called sodium extract. The sodium extract is subjected to further chemical analysis to decide whether the organic compound has foreign element or not.

Why is sodium extract usually alkaline?

Why is the sodium extract alkaline in nature? Ans. Because the organic compound is fused with sodium metal and then it is extracted with water. The unreacted metal reacts with water and forms an alkaline solution.

Can potassium replace sodium in Lassaignes test?

Can we use potassium in place of sodium in Lassaigne’s test? Ans. No. Potassium is too reactive metal and hence dangerous to use.

Why is sodium fusion extract alkaline?

Why do we prepare sodium extract for detection of extra element in organic compound?

Why is conc HNO3 added to sodium extract?

HNO3 is added to sodium extract before adding silver nitrate for testing halogens, to decompose any NaCN or Na2S if present.

What is the function of the addition of FeSO4 in the detection of nitrogen?

Freshly prepared FeSO4 is used to test nitrogen since, FeSO4 on exposure to the atmosphere, it readily oxidized to ferric sulphate and does not support in the formation of the brown ring.

What is Lassaigne’s test used to detect?

The Lassaigne’s test helps to detect Nitrogen, Sulphur, and Halogens in the organic compounds. Here, sodium metal (Na) is heated in the presence of the organic compound inside a fusion tube. The primary objective of this test is that all the available elements are being converted by Sodium metal (Na) into the ionic state.

How to perform Lassaigne’s test using SFE and FeCl3?

To a portion of SFE, freshly prepared ferrous sulphate, FeSO 4 solution is added and warmed. Then about 2 to 3 drops of FeCl 3 solution are added and acidified with conc. HCl. The appearance of a Prussian blue color indicates the presence of nitrogen. 1) In Lassaigne’s test, afresh solution of fresh solution of FeSO 4 must be used.

Why diazonium salts do not give CN – ion test?

This is because both C and N are required to form CN – ion. This test is not given by diazonium salts as they decompose to give nitrogen gas on heating. The extract is treated with sodium nitroprusside. The appearance of violet colour indicates the presence of sulphur. The following reaction occurs:

How do you test for fluorine in sodium fusion extract?

LASSAIGNE’S TEST FOR HALOGENS The sodium fusion extract, SFE can be used to detect the presence of chlorine, bromine and iodine but not fluorine. To detect their presence, the SFE is first acidified with HNO 3 and then added with AgNO 3 solution.