Aniline is usually purified by

Give the answer of the following questions in short:
$(i)$ When is simple distillation used?
$(ii)$ When is fractional distillation used?
$(iii)$ Which liquid is obtained first in fractional distillation?
$(iv)$ Which liquid is cooled first in fractional distillation?
$(v)$ What happens in the fractional column?

The method used for the separation of the mixture of products ($B$ and $C$) obtained in the following reaction is:

Write about thin layer chromatography $(TLC)$.

Glycerol is separated in soap industries by

The technique used for purification of steam volatile water immiscible substances is: