What is the final product obtained by the reduction of acetaldehyde with sodium and alcohol?

Based on the reaction sequence shown,select the incorrect statement about $P_2$. The reaction starts with cyclohexanone reacting with $Mg-Hg/H_2O$ to form $P_1$,which then reacts with conc. $H_2SO_4$ and heat to form $P_2$.

Identify the product $A$ in the following reaction:
$\text{Substrate} \xrightarrow{MnO_2} A$
(The substrate is a benzene ring with a $-OH$ group,a $-COOH$ group,and a $-CH(CH_2CH_3)CHO$ group attached to it.)

Identify the product of the following reaction: $CH_3-CH=CH-CH_2-C \equiv N \xrightarrow[H_3O^{+}]{\text{DIBAL-H}} \text{Product}$

Which product is obtained by the reduction of propionaldehyde with amalgamated zinc and concentrated $HCl$?

The major product of the following reaction is: