Aromatic Compounds Containing Nitrogen - Result Question 35
####36. Match the compounds in Column I with their characteristic test(s)/reaction(s) given in Column II.
(2008, 6M)
| Column I | Column II | ||
|---|---|---|---|
| (A) | (P) | Sodium fusion extract of the compound gives Prussian blue colour with $FeSO _4$ |
|
| (B) | (q) | Gives positive $FeCl _3$ test |
|
| (C) | $(r)$ | Gives white precipitate with $AgNO _3$ |
|
| (D) | (s) | Reacts with aldehydes to form the corresponding hydrazone derivative |
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Answer:
Correct Answer: 36. $A \rightarrow r, s \quad B \rightarrow p, q \quad C \rightarrow p, q, r \quad D \rightarrow p$
Solution:
- Sodium fusion extract gives Prussian blue colouration, nitrogen and carbon both present in the compound. Phenolic group and salt of carboxylic acid gives $FeCl _3$ test. Chloride salt gives white precipitate of $AgCl$ on treatment with $AgNO _3$. Hydrazone formation occur effectively at $pH=4.5$. The reaction proceeds in that condition only when $H^{+}$concentration is just sufficient to activate the following enolisation.
As $H^{+}$concentration rises sufficiently, a large number of molecules of hydrazine gets converted into hydrazinium ion which is not nucleophilic and reaction becomes impossible. Further low concentration of $H^{+}$(in the case of 2,4-dinitrophenyl hydrazinium bromide) is not effective to proceed elimination.
