$(i)$ Name a technique to separate a mixture of two or more miscible liquids for which the difference in boiling points is less than $25\, K$.
$(ii)$ Describe the structure of the column used in the above technique. Why is it used?

(N/A) $(i)$ The technique used is fractional distillation.
$(ii)$ The fractionating column is a glass tube packed with glass beads or other materials that provide a large surface area. It is fitted between the distillation flask and the condenser.
It is used because it provides a large surface area for the vapours to cool and condense repeatedly,allowing for better separation of liquids with boiling points close to each other.