Question

Write a simple chemical test to distinguish between methylamine and aniline.

Hint:

- Aniline undergoes diazotization and forms a coloured dye. - Methylamine does not form a diazonium salt.

Answer 1

Step 1: Diazotization of Aniline - Aniline reacts with nitrous acid (\( HNO_2 \)) at low temperature (0–5°C) to form benzene diazonium chloride. \[ \text{C}_6\text{H}_5\text{NH}_2 + HNO_2 \rightarrow \text{C}_6\text{H}_5\text{N}_2^+Cl^- \] Step 2: Coupling Reaction with Phenol - The diazonium salt reacts with phenol to form an orange dye. - Methylamine (\( CH_3NH_2 \)) does not undergo diazotization and does not form the orange dye.