Question

Which among the following method is used to obtain paraffin, diesel and fuel oil from crude oil?

Answer 1

If the difference between the boiling points of the mixture of miscible liquids is less than $25{}^{\circ }\text{C}$, then fractional distillation is used to separate components of the mixture.

Crude oil which is drilled out from the depth of the Earth, is a mixture of miscible liquids (paraffin, diesel, fuel oil, etc.) and the difference in the boiling points of these components is less than $25{}^{\circ }\text{C}$.
Hence, fractional distillation is the method used to obtain the different components (paraffin, diesel, fuel oil etc.) from crude oil.