What is the nature of an aqueous solution of methylamine?

The reason for the solubility of ethylamine in water is......

The product $(A)$ is:

Identify product $B$ in the following reaction: $Aniline$ $\xrightarrow{NaNO_2 + HCl, 273 \ K} A$ $\xrightarrow{H_2O, \Delta} B + N_2 \uparrow$

Several factors (steric,electronic,orbital interactions,etc.) can affect the inversion barrier of an amine. In the given pairs,which data is correctly placed?

Ammonolysis of alkyl halides followed by treatment with $NaOH$ solution can be used to prepare primary,secondary,and tertiary amines. The purpose of $NaOH$ in the reaction is: