Give the structures of A and B in the following sequence of reactions:
$\left(\mathrm{a}\right) {\mathrm{CH}}_3\mathrm{COOH}\underset{∆}{\overset{{\mathrm{NH}}_3}{\to }}\mathrm{A}\stackrel{\mathrm{NaOBr}}{\to }\mathrm{B}$
(b)${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{NO}}_2\stackrel{\mathrm{Fe}/\mathrm{HCL}}{\to }\mathrm{A}\underset{0°-5°\mathrm{C}}{\overset{{\mathrm{NaNO}}_2+\mathrm{HCL}}{\to }}\mathrm{B}$
(c) ${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{N}}_2^{+}{\mathrm{Cl}}^{-}\frac{\mathrm{CuCN}}{\mathrm{\Delta }}\mathrm{A}\stackrel{{\mathrm{H}}_2\mathrm{O}/{\mathrm{H}}^{+}}{\to }\mathrm{B}$

OR

(a) How will you distinguish between the following pairs of compounds :
(i) Aniline and Ethanamine
(ii) Aniline and N-methylaniline

(b) Arrange the following compounds in decreasing order of their boiling points:
Butanol, Butanamine, Butane