Glycerol reacts with conc. $HNO_3$ and conc. $H_2SO_4$ to form

Identify $Z$ in the following sequence of reactions:
$CH_{3}-CH_{2}-CH_{2}-OH$ $\xrightarrow{PCl_{3}} X$ $\xrightarrow[\Delta]{alco.KOH} Y$ $\xrightarrow[H-OH/heat]{conc.H_{2}SO_{4}} Z$

In the following sequence of reaction,$Z$ $\xrightarrow{PCl_5} X$ $\xrightarrow[\Delta]{\text{Alc. KOH}} Y$ $\xrightarrow{H_2O/H^{+}} Z$ (Major),$Z$ is:

$4$-chloro-butan-$1$-ol $+ NaOH \to (B)$. The product $(B)$ of the above reaction is:

Which of the following compounds has the highest boiling point?

Which among the following reactions occurs by the breaking of $C-O$ bond in alcohol?