In the presence of a small amount of phosphorus,aliphatic carboxylic acids react with chlorine or bromine to yield a compound in which $\alpha$-hydrogen has been replaced by a halogen. This reaction is known as:

The product $(C)$ of the following reaction is:

Identify $B$ in the following sequence of reactions.
Acetic acid $\xrightarrow[\Delta]{\text{Thionyl chloride}} A$ $\xrightarrow{\text{Ammonia}} B$

Carboxylic acids react with diazomethane to form

$A$ compound $(A)$ has the molecular formula $C_2H_4O_2$ and it gives the following reactions:
$(i)$ Addition of the above compound to a sodium carbonate solution gives effervescence of $CO_2$ gas and forms compound $(P)$.
$(ii)$ When compound $(P)$ is heated with sodalime,it gives gas $(Q)$. Identify $(A)$,$(P)$,and $(Q)$ and provide the reactions.

What are $A$ and $B$ in the following reaction sequence?
$CH_3COOH$ $\xrightarrow{A} X$ $\xrightarrow[H^{+}]{Y} \underset{\text{(Analgesic drug)}}{B}$