Identify $P_3$ in the following reaction sequence:

In the following reaction sequence,$CH_3CH_2OH$ $\xrightarrow{P + I_2} A$ $\xrightarrow[\text{dry ether}]{Mg} B$ $\xrightarrow{HCHO} C$ $\xrightarrow{H_2O} D$,the compound $D$ is:

What is the major product of the following reaction?

Consider the following reactions:
$X + HCl \xrightarrow{\text{Anhydrous } AlCl_3} C_2H_5Cl$
$Y \xrightarrow{\text{Anhydrous } ZnCl_2 / HCl} C_2H_5Cl$
$Y$ can be converted to $X$ on heating with which of the following reagents?

Which of the following compounds is most reactive toward acid-catalyzed dehydration?

When phenyl magnesium bromide reacts with $t-$butanol,the product would be