When is fractional distillation used?

Describe the method that can be used to separate two compounds with different solubilities in a solvent $S$.

Which of the following is not an element?

The separation of two coloured substances was done by paper chromatography. The distances travelled by solvent front,substance $A$ and substance $B$ from the base line are $3.25 \ cm$,$2.08 \ cm$ and $1.05 \ cm$ respectively. The ratio of $R_{f}$ values of $A$ to $B$ is $.........$

$A$ mixture of sand and sulphur may best be separated by:

You have a mixture of three liquids $A$,$B$,and $C$. There is a large difference in the boiling points of $A$ and the rest of the two liquids,i.e.,$B$ and $C$. The boiling points of liquids $B$ and $C$ are quite close. Liquid $A$ boils at a higher temperature than $B$ and $C$,and the boiling point of $B$ is lower than that of $C$. How will you separate the components of the mixture?