Chemistry - AMINES Question with Solution | TestHub
An organic compound 'A' contains nitrogen and chlorine. It dissolves readily in water to give a solution that turns litmus red. Titration of compound 'A' with standard base indicates that the molecular weight of 'A' is . When a sample of 'A' is treated with aq. NaOH , a liquid separates which contains N but not Cl . Treatment of the obtained liquid with nitrous acid followed by phenol gives orange precipitate. The compound ' A ' is :
Options:
Answer:
Solution:
Explanation:
The question asks to identify the structure of an organic compound 'A' based on its properties: molecular weight (≈131), acidic nature (turns litmus red), presence of N and Cl, and chemical reactions (loses Cl upon treatment with NaOH and forms an orange precipitate via diazotization followed by coupling with phenol).
Concept:
This question is based on:
(1) Acid base reaction of aniline and anilinium ion.
(2) Diazotization and coupling reaction.
Solution: −
The compound 'A' turns litmus red, so it's acidic, meaning it's likely an amine salt. The molecular weight is 131±2. It contains N and Cl, but treatment with aq. NaOH yields a liquid with N but no Cl, confirming Cl is present as an ionic salt like Cl- . The obtained liquid (aniline-like) reacts with HNO2 (diazotization) followed by phenol (coupling) to give an orange precipitate (an azo dye), which is characteristic of aniline (C6H5NH2 ).
