Hydrocarbons: Alkanes and Alkenes: Question 6
Syllabus 11.3
An airline's fuel supplier buys petroleum fractions from a nearby oil refinery. One of these fractions is loaded onto tanker trucks and delivered to the airport, where it is used as the fuel burned in aircraft engines.
Which fraction obtained from the fractional distillation of petroleum is normally used as fuel for aircraft?
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Worked solution
Step 1: Recall the fractions obtained from petroleum and their typical uses
Fractional distillation separates petroleum into fractions with different chain lengths, boiling points and uses:
- Refinery gas: shortest chains, most volatile, used as a fuel for heating and cooking.
- Gasoline/petrol: used as a fuel for cars.
- Naphtha: used as a chemical feedstock for making other chemicals, not usually burned as a fuel itself.
- Kerosene (paraffin): used as a fuel for aircraft (jet engines).
- Diesel oil/gas oil: used as a fuel for diesel engines.
- Fuel oil: used as a fuel for ships and for home heating systems.
- Lubricating oil: used to make lubricants, waxes and polishes.
- Bitumen: longest chains, highest boiling point, used for making roads and for roofing.
Step 2: Match the description to the correct fraction
The question describes a fraction that is burned directly as the fuel inside aircraft engines. This matches kerosene (paraffin) exactly.
Step 3: Check why the other options are wrong
- A (Refinery gas): this short-chain fraction is used for heating and cooking, not for aircraft.
- B (Naphtha): this fraction is mainly a chemical feedstock, not a fuel burned in engines.
- D (Bitumen): this is the thickest, highest-boiling fraction, used for road-making, and could not even flow into an aircraft engine.
Final answers
- Kerosene (paraffin) is the fraction used as aircraft fuel, .