Final answer:
Petrol burns off at a higher temperature than kerosene and diesel during fractional distillation.
Step-by-step explanation:
During fractional distillation, the components of crude oil are separated based on their boiling points.
The temperature at which a substance burns off depends on its boiling point.
Generally, petrol has a lower boiling point than kerosene and diesel, so it burns off at a higher temperature during fractional distillation.