Give one good chemical test to distinguish between the following pair of compounds: Methylamine and dimethylamine.

Explanation

These can be distinguished by the carbylamine test. Ethylamine is primary `(1^(@))` amine therefore, it gives carbylamine test i.e., when heated with an alcoholic solution of KOH and `CHCl_(3)`, it gives an unpleasant foul smell of isocyanide which is easily detectable.
`C_(2)H_(5)NH_(2)+CHCl_(3)+alc.KOHrarrC_(2)H_(5)NC+"Ethyl isocyanide "3KCl+3H_(2)O`
On the other hand, diethylamine is a secondary `(2^(@))` amine and hence does not give this test.