Which reagent is used in the conversion of $C_2H_5NH_2$ to $C_2H_5Cl$?

In the reaction $CH_3Br + KCN_{(alc)} \to X \xrightarrow[Na + C_2H_5OH]{reduction} Y$,identify $Y$.

Identify $X$ in the following reaction sequence:

Predict the product of the following reaction:
$C_6H_5NHCH_3 + NaNO_2 + HCl \rightarrow \text{Product}$

For the reaction shown,the correct order of the set of reagents for the conversion is:

When a primary amine is heated with $NaNO_2/HCl$,a gas is evolved with brisk effervescence. Identify the gas.
$R-NH_2 \xrightarrow{NaNO_2/HCl} ..................$