The latest technique for the purification of organic compounds is

Which of the following statements is correct for paper chromatography?

Glycerol boils at $290\,^oC$ with slight decomposition. Impure glycerin can be purified by:

From the figure of column chromatography given below,identify the incorrect statements.
$A.$ Compound '$c$' is more polar than '$a$' and '$b$'
$B.$ Compound '$a$' is least polar
$C.$ Compound '$b$' comes out of the column before '$c$' and after '$a$'
$D.$ Compound '$a$' spends more time in the column
Choose the correct answer from the options given below :-

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:

In chromatography,what does $R_f$ stand for?