Glycerol boils at $290\,^{\circ}C$ with slight decomposition. Impure glycerine can be purified by

Write about thin layer chromatography $(TLC)$.

Give a brief description of the principles of the following techniques taking an example in each case.
$(a)$ Crystallisation
$(b)$ Distillation
$(c)$ Chromatography

Explain partition chromatography. What is partition chromatography? Describe paper chromatography.

Identify the correct statements from the following:
$(i)$ Electromeric effect is a permanent effect.
$(ii)$ Hyperconjugation is a temporary effect.
$(iii)$ Fractional distillation is used to separate two liquids from a mixture if the difference in their boiling points is less.
$(iv)$ Different compounds are adsorbed on an adsorbent to different extents.

In chromatography technique,the purification of a compound is independent of: