Aim: To prepare sodium fusion extract.
Chemicals: Sodium metal, distilled water.
Apparatus:
- Beaker
- Sodium fusion tube
- China dish
- Tripod stand
- Filter paper
- Test tube holder
Principle: We prepare sodium extract because the elements in the organic compound are in the covalent form in which they cannot be detected but when the organic compound is fused with sodium metal, sodium salt is formed which organic compound is converted into ionic salt and hence elements can be easily detected.
Note: When the organic compound is heated with Na, the elements such as nitrogen, Sulphur and halogens if present in the compounds are converted into sodium salts which are soluble in water. The aqueous solution is then used to identify these elements. Therefore fusion of and organic compound with sodium metal required in Lassaigne test.
Procedure:
- A small piece of dry sodium metal is heated with an organic compound in a fusion tube for 2-3 minutes.
- The red hot tube is plunged in to distilled water contained in a china dish.
- The contained of the china dish is boiled cooled and filtered.
- The filtrate is known as sodium fusion extract.
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