$A$ flask contains a mixture of isohexane and $3-$methylpentane. One of the liquids boils at $63^{\circ}C$ while the other boils at $60^{\circ}C$. What is the best way to separate the two liquids and which one will be distilled out first?

State whether the following statements regarding fractional distillation are True or False:
$(i)$ The freezing of vapour of a liquid with a high boiling point takes place first.
$(ii)$ In the column,the more volatile liquid is present in a higher concentration in the vapour phase at higher levels.
$(iii)$ The condensed liquid flows down and provides heat to the vaporizing liquid.
$(iv)$ The liquid with the highest boiling point reaches the top of the column.

On a thin layer chromatographic plate,an organic compound moved by $3.5 \ cm$,while the solvent moved by $5 \ cm$. The retardation factor of the organic compound is . . . . . . $\times 10^{-1}$.

What is the difference between distillation,distillation under reduced pressure,and steam distillation?

$A$ mixture of dichloromethane and aniline can be separated by

Fill in the blanks:
$1$. In formulas and reactions,the electron pair displacement is indicated by a curved arrow,and the single electron displacement is indicated by a ..........
$2$. There are more than .......... plates in the columns of fractional distillation.
$3$. Fractional distillation is used for the separation of liquids with a .......... difference in boiling points,and simple distillation is used for the separation of liquids with a .......... difference in boiling points.
$4$. The .......... technique is applied to separate different fractions of crude oil in petroleum.