Methyl ethyl ketone is prepared by the oxidation of

Identify $Z$ in the following sequence of reactions.
$C_2H_4Br_2$ $\xrightarrow[\text{(ii) } NaNH_2]{\text{(i) alc- } KOH} X$ $\xrightarrow[\text{Red hot}]{\text{Fe tube, } 873 \ K} Y$ $\xrightarrow[\Delta]{\left(CH_3CO\right)_2O / \text{Anhyd-} AlCl_3} Z$

Explain the method of preparation of aldehydes and ketones from nitrile compounds.

What are $A$ and $B$ in the following reaction sequence?
$\text{Propionitrile} + A$ $\longrightarrow B$ $\xrightarrow{H_3O^{+}} \text{propiophenone}$

In the reaction $CH_3CN + 2H \underset{\text{Ether}}{}$ ${\xrightarrow{HCl}} X$ $\xrightarrow{\text{Boiling } H_2O} Y$; the product $Y$ is

The major product of the following chemical reaction is
$CH_{3}CH_{2}CN \xrightarrow[(3) Pd/BaSO_{4}, H_{2}]{(1) H_{3}O^{+}, \Delta \quad (2) SOCl_{2}} ?$