The oxidation of benzyl chloride with lead nitrate gives

The reaction of benzene with $CO$ and $HCl$ in the presence of anhydrous $AlCl_3$ gives a compound $X$. $X$ can also be obtained from which of the following reactions?

What is the compound formed when a mixture of calcium acetate and calcium formate is subjected to dry distillation?

For the reaction sequence: $P$ $\xrightarrow[2. H_3O^+]{1. CH_3MgBr} R$ $\xrightarrow[2. \Delta]{1. \text{dil. } NaOH} \text{4-methylpent-3-en-2-one}$,identify $P$.

Describe the method of preparation of aldehydes from nitrile and ester compounds by reaction with $DIBAL-H$.

Consider the following reaction:
$C_6H_5COCl \xrightarrow{H_2, Pd/BaSO_4} A$
The product $A$ is: