To solve this problem, we need to understand the chemical reactions given and identify how the compound (X) is transformed into the lactone (Y) via these reactions.
The reactions are as follows:
\(\text{Compound (X) reacts with formaldehyde (HCHO) and KOH.}\) This is an example of the Cannizzaro reaction where an aldehyde in the presence of a strong base disproportionates into alcohol and acid. However, this is a condensation type leading to further reactions.
\(\text{Reaction with KCN (in alcohol)}.\) This step typically introduces a cyano (-CN) group to the molecule.
\(\text{Finally, acid hydrolysis (H}_3\text{O}^+)\) converts the cyano group into a carboxylic acid group.
