Question

Test to know presence of phosphorus in sodium extract

Answer 1

Answer:

Detection of Sulphur Thus, Lassaigne's solution contains sodium sulphide. The sodium extract is acidified with acetic acid and lead acetate is added. A black precipitate of lead sulphide (PbS) is formed if sulphur is present in the organic compound.

Answer 2

Explanation:

To check whether phosphorus is present in the organic compound or not:

The organic compound is treated with sodium peroxide(Na2O2NaX2OX2). Phosphorus gets converted to sodium phosphate. Then we carry out the same procedure that we do to identify phosphate anion.

The aqueous extract is heated with concentrated nitric acid and ammonium molybdate. A canary yellow precipitate of ammonium phosphomolybdate is obtained. This yellow precipitate helps us conclude that Phosphorus was present in the organic compound.

Reactions:

Na3PO4+3HNO3⟶H3PO4+3NaNO3