Detection of Halogens in Organic Compound by Lassaigne’s Solution – Silver Nitrate Test

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Detection of Halogens: (Silver Nitrate Test)

The following steps help in the detection of halogens in an organic compound.

Lasseigne’s solution or sodium fusion extract is used for preparation for the detection of nitrogen, sulphur and halogens in the given organic compound.

Also, Read Preparation of Lassaigne’s Solution


Step 1:

Take Lasseigne’s filtrate in a test tube and add a few drops of concentrated nitric acid (HNO3).

Step 2:

Boil  & then cool the solution.

Step 3:

Then add silver nitrate( AgNO3) solution.

Presence of Chlorine:

If the organic compound contains chlorine then sodium chloride formed during the preparation of Lassaigne’s extract reacts with the silver nitrate to form a white precipitate of silver chloride.

Chlorine Confirmatory Test:

Presence of Bromine:

Formation of pale yellow precipitate of silver bromide ( AgBr ).

Bromine Confirmatory Test:

Pale yellow precipitate partially soluble in NH4OH indicates the presence of bromide ions.

Presence of Iodine:

Iodine Confirmatory Test:

Deep yellow precipitate insoluble in NH4OH indicates the presence of iodide ions.

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