Which one of the following can be purified by sublimation?

Fill in the blanks:
$1$. In differential extraction from two layers,the .......... layer is above because .............
$2$. The organic solvent used in differential extraction is .......... in water.
$3$. If an organic compound is ......... soluble in an organic solvent,then the continuous extraction technique is used.
$4$. ........ solution is added to produce the precipitate of halide for the estimation of halogen.

Which technique is used for the separation of a compound present in an aqueous solution?

What is column chromatography?

State whether the following statements are True or False:
$(i)$ The boiling points of chloroform and aniline are $334 \ K$ and $457 \ K$ respectively.
$(ii)$ The vapour of chloroform is obtained after aniline in simple distillation.
$(iii)$ Chloroform is more volatile than aniline.

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