Acetaldehyde $(CH_3CHO)$ reacts with:

$A$ molecule $(X)$ with the following structure is hydrolyzed under mild acidic conditions to produce $(Y)$ and $(Z)$. Identify the correct statements about $(Y)$ and $(Z)$.

The reaction of $CH_3CH_2CHO$ with $PCl_5$ yields a product. Identify the type of dihalide formed.

What is the name of the reaction when $C_6H_5CHO$ (benzaldehyde) changes into $C_6H_5CH_2OH$ (benzyl alcohol)?

The best reagent to convert $pent-3-en-2-ol$ into $pent-3-yn-2-one$ is

In the reaction sequence,
the major products $X$ and $Y$ respectively are