What is the characteristic of $R_f$ value?

State whether the following statements are True or False:
$(i)$ The purification of a solid is done by crystallisation.
$(ii)$ Crystallisation purifies the solid and distillation purifies the liquid.
$(iii)$ $A$ liquid is purified by sublimation.
$(iv)$ To separate a mixture of ammonium chloride and sodium chloride,the distillation method is applied.

Two products $X$ and $Y$ are formed in the following reaction sequence: Benzene + $CH_3Cl \xrightarrow{Anhydr. AlCl_3} W \xrightarrow{dil. HNO_3/dil. H_2SO_4, warm} X + Y$. The suitable method that can be used for the separation of products $X$ and $Y$ is:

Match List-$I$ with List-$II$.

List-$I$ (Purification technique)	List-$II$ (Mixture of organic compounds)
$(A)$ Distillation (simple)	$(I)$ Diesel + Petrol
$(B)$ Fractional distillation	$(II)$ Aniline + Water
$(C)$ Distillation under reduced pressure	$(III)$ Chloroform + Aniline
$(D)$ Steam distillation	$(IV)$ Glycerol + Spent-lye

Choose the correct answer from the options given below $:$

If a liquid compound decomposes at its boiling point,which method$(s)$ can you choose for its purification? It is known that the compound is stable at low pressure,steam volatile,and insoluble in water.

What is column chromatography?