Which of the following compounds on boiling with hydrochloric acid forms a ketone?

The major product $(x)$ in the following reaction is:

In the sequence of the following reactions,$X$ and $Y$ are respectively: $CH_3OH$ $\xrightarrow{HI} CH_3I$ $\xrightarrow{KCN} CH_3CN$ $\xrightarrow{\text{reduction}} X$ $\xrightarrow{HNO_2} Y$

Identify the correct decreasing order of basic strength of methyl-substituted amines in an aqueous solution.

In the following compounds,the order of basicity is:
$I$: Piperidine
$II$: Pyridine
$III$: Morpholine
$IV$: Pyrrole

The correct order of increasing basic nature for the bases $NH_{3}$,$CH_{3}NH_{2}$ and $(CH_{3})_{2}NH$ in aqueous solutions is: