(a) Write the structures of the main products of the following reactions:

(b) Give a simple chemical test to distinguish between Aniline and N, N-dimethylaniline.
(c) Arrange the following in the increasing order of their pKb values
${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{NH}}_2,{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{NH}}_2,{\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{NHCH}}_3$