Answer:
Fractional distillation
Step-by-step explanation:
Petrol and diesel can be separated by using a process referred to as distillation.
While separating petrol and diesel using distillation, the mixture is kept in a fractionating column.
The one with the lowest boiling point evaporates first and goes to the higher level followed by condensation at lower temperature, while the one with higher boiling point has high condensation point, but condenses at a lower level.
And that is how to separate them, in a process more specifically referred to as " fractional distillation "
Hope that helps!