Which one of the following techniques is not used to spot components of a mixture separated on a thin layer chromatographic plate?

Which of the following statements are correct?
$A$. Glycerol is purified by vacuum distillation because it decomposes at its normal boiling point.
$B$. Aniline is purified by steam distillation as it is immiscible in water.
$C$. Ethanol can be separated from an ethanol-water mixture by azeotropic distillation because it forms an azeotrope.
$D$. An organic compound is pure if the mixed $M.P.$ remains the same.
Choose the most appropriate answer from the options given below:

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:

On which principle does the solute move on chromatography paper?

What is a chromatogram?

The species that exhibits the highest $R_f$ value in a thin layer chromatogram using a non-polar solvent on a silica gel plate is