Question

During Lassaigne's test, the elements present in an organic compound are converted from:

• A. Covalent form to ionic form
• B. Covalent form to covalent form
• C. Ionic form to ionic form
• D. Ionic form to covalent form

Hint:

Lassaigne's test converts covalently bonded elements into ionic sodium salts for their detection.

Answer 1

The Correct Option is A

Step 1: Understand Lassaigne's test.
Lassaigne's test is used for the detection of elements like: \[ N,\ S,\ Cl,\ Br,\ I \] in organic compounds.

Step 2: Understand the problem in organic compounds.
In organic compounds, elements like nitrogen, sulphur and halogens are usually present in covalent form. Covalent compounds do not easily give ionic reactions directly. Therefore, they cannot be detected directly by ordinary ionic tests.

Step 3: Role of sodium fusion.
In Lassaigne's test, the organic compound is fused with sodium metal. During sodium fusion, covalent elements are converted into water-soluble ionic sodium salts. For example: \[ Na + C + N \rightarrow NaCN \] \[ 2Na + S \rightarrow Na_2S \] \[ Na + X \rightarrow NaX \] where: \[ X=Cl,\ Br,\ I \]

Step 4: Final conclusion.
Thus, Lassaigne's test converts covalent elements in organic compounds into ionic compounds. Therefore, the correct answer is: \[ \text{Covalent form to ionic form.} \]