In chromatography,what does $R_f$ stand for?

Explain the sublimation technique used for the purification of organic compounds.

Write about thin layer chromatography $(TLC)$.

Aniline is usually purified by

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$:
Assertion $(A):$ $A$ simple distillation can be used to separate a mixture of propanol and propanone.
Reason $(R):$ Two liquids with a difference of more than $20^{\circ}C$ in their boiling points can be separated by simple distillation.
In the light of the above statements,choose the most appropriate answer from the options given below:

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