Identify the product $A$ in the following reaction:
Aniline $\xrightarrow{(CH_3CO)_2O / \text{pyridine}} A$

Compare the basicity of aryl amines with alkyl amines.

What is the role of pyridine in the acylation reaction of amines?

Consider the three aromatic molecules ($P$, $Q$ and $R$) whose structures are given below. The correct order regarding the reactivity of these compounds with $Ph-N\equiv N^{(+)}Cl^{(-)}$ under optimum but slightly acidic medium is:

Unpleasant smelling carbylamines are formed by heating alkali and chloroform with

Identify the compound from the following having the lowest boiling point.