Identify the major product obtained when ethyl amine $(CH_3CH_2NH_2)$ is reacted with an excess of methyl iodide $(CH_3I)$?

In the reaction sequence $A$ $\xrightarrow{Sn/HCl} B$ $\xrightarrow{HNO_2, 0^{\circ}C} C$ $\xrightarrow{C_2H_5OH} C_6H_6$,identify the functional groups present in $A, B,$ and $C$.

The correct order of basicity of the various nitrogen atoms in $LSD$ is:

The product obtained by the electrolytic reduction of nitrobenzene in the presence of $H_2SO_4$ is:

Identify the correct decreasing order of $pK_b$ values of the following compounds.

$A$ student performed an analysis of an aliphatic organic compound '$X$' which, upon analysis, gave $C=61.01\%$, $H=15.25\%$, $N=23.74\%$. This compound, on treatment with $HNO_2/H_2O$, produced another compound '$Y$' which did not contain any nitrogen atom. However, the compound '$Y$' upon controlled oxidation produced another compound '$Z$' that responded to the iodoform test. The structure of '$X$' is: