Diethyl oxalate is used for distinguishing primary,secondary and tertiary

Ammonia reacts with which of the following reagents to give a brown precipitate?

Give one chemical test to distinguish between the following pairs of compounds:
$(i)$ Methylamine and dimethylamine
$(ii)$ Secondary and tertiary amines
$(iii)$ Ethylamine and aniline
$(iv)$ Aniline and benzylamine
$(v)$ Aniline and $N$-methylaniline.

Cyclohexylamine and aniline can be distinguished by

Which amine does not react with Hinsberg reagent?

$A$ compound $X$ on reaction with chloroform and $NaOH$ gives a compound with a very unpleasant odour. $X$ is