Which one of the following on treatment with $50 \% \text{ aq. } NaOH$ yields the corresponding alcohol and salt of carboxylic acid?

In the given reaction $CH_3-CH_2-C(=O)-CH_2-COOC_2H_5$ $\xrightarrow{[X]} (A)$ $\xrightarrow{(i) LiAlH_4, (ii) H_2O/H^{+}} CH_3-CH_2-C(=O)-CH_2-CH_2OH + C_2H_5OH$,$[X]$ will be:

In the given reaction,what is $Y$?
$(P)$ $\xrightarrow{\Delta} X$ $\xrightarrow{Zn-Hg/HCl} Y$

Among the following,the marked proton of which compound shows the lowest $pK_{a}$ value?

$A$ compound $A$ with molecular formula $C_{10}H_{13}Cl$ gives a white precipitate on adding silver nitrate solution. $A$ on reacting with alcoholic $KOH$ gives compound $B$ as the main product. $B$ on ozonolysis gives $C$ and $D$. $C$ gives Cannizzaro reaction but not aldol condensation. $D$ gives aldol condensation but not Cannizzaro reaction. $A$ is:

Which is the major product obtained by hydrolysis of the compound formed by the reaction between formaldehyde and ethyl magnesium bromide?