The purification method based on the following physical transformation is $:$
$\text{Solid} (X)$ $\xrightarrow{\text{Heat}} \text{Vapour} (X)$ $\xrightarrow{\text{Cool}} \text{Solid} (X)$

What is meant by the term "chromatography"?

In the given $TLC$ plate,the distances of spots $A$ and $B$ from the base line are $4 \ cm$ and $6 \ cm$,respectively. The distance moved by the solvent front from the base line is $8 \ cm$. If the $R_f$ value of $B$ is $x \times 10^{-1}$ times that of $A$,find the value of $x$.

State whether the following statements regarding steam distillation at reduced pressure are True or False:
$i$. It is used in the soap industry.
$ii$. Water pumps,vacuum pumps,or air pumps are used.
$iii$. Liquids with high boiling points do not decompose.
$iv$. The liquid is decomposed.
$v$. The liquid is boiled at a low temperature.

To separate different fractions of crude oil in the petroleum industry,the method used is:

Which apparatus is used to reduce pressure in distillation under reduced pressure?