Glycerol is purified by

From the figure of column chromatography given below,identify the incorrect statements.
$A.$ Compound '$c$' is more polar than '$a$' and '$b$'
$B.$ Compound '$a$' is least polar
$C.$ Compound '$b$' comes out of the column before '$c$' and after '$a$'
$D.$ Compound '$a$' spends more time in the column
Choose the correct answer from the options given below :-

Which of the following statements about $TLC$ are correct?
$(i)$ Glycine is identified on $TLC$ plate due to its colour.
$(ii)$ Amino acids can be detected by spraying the $TLC$ plate with $Ninhydrin$ solution.
$(iii)$ The retardation factor $(R_f)$ is the ratio of the distance travelled by the solute to that of the solvent from the base line.
$(iv)$ Sodium chloride is commonly used as an adsorbent.

Which purification method is used to separate liquids that have a sufficient difference in their boiling points?

Which technique among the following is most appropriate for the separation of a mixture of $100 \ mg$ of $p-$nitrophenol and picric acid?

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?