In chromatography,what does $R_f$ stand for?

What is chromatography used for?

In thin layer chromatography,a substance moved by a distance of $4 \ cm$,whereas the solvent moved by a distance of $5 \ cm$. Then the value of retardation factor $(R_f)$ is

Among the following,in which type of chromatography,both stationary and mobile phases are in liquid state?

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$(A)$ Chloroform and Aniline	$(I)$ Steam distillation
$(B)$ Benzoic acid and Naphthalene	$(II)$ Sublimation
$(C)$ Water and Aniline	$(III)$ Distillation
$(D)$ Naphthalene and Sodium chloride	$(IV)$ Crystallisation

Given below are two statements:
Statement $I$: Vapours of the liquid with higher boiling point condense before vapours of the liquid with lower boiling points in fractional distillation.
Statement $II$: The vapours rising up in the fractionating column become richer in high boiling component of the mixture.