Question

Give one chemical test to distinguish between the following pairs of compounds:

(i) Ethanol and 2 propanols.
(ii) Aniline and ethylamine.

Answer 1

(i)

Ethanol	2-Propanol
When treated with Lucas reagent (anhy. ZnCl2 and cone. HCl), ethanol gives turbidity after heating.	When treated with Lucas reagent, 2-propanol gives turbidity within five minutes without heating.

 

(ii) Aniline and ethylamine can be distinguished using the azo-dye test.

Aniline	Ethylamine
Aniline is treated with HN02 (NaNO2 + dil. HCl) at 0-5°C to give’ benzene diazonium chloride, which on further treatment with an alkaline solution of (3-naphthol gives red dye.	Ethylamine gives a brisk effervescence due to evolution of N2 gas under similar conditions.