Which fraction of crude oil is commonly used as domestic gas for cooking?

• A. Gasoline — used as domestic heating fuel.
• B. Petrol — used for domestic heating.
• C. Diesel — used for cooking.
• D. Refinery gas — used as domestic fuel or for cooking.

Answer: (D)

Crude oil is separated into fractions with different boiling points, giving light hydrocarbon gases and liquids that are suitable for various uses. Among these, refinery gas is the fraction used as domestic cooking gas. It is mainly propane and butane, stored under pressure as a liquid and released as gas to fuel burners. This makes it convenient for home use, with a controllable flame and safe storage in cylinders. The other options are fuels for engines, not household cooking fuels: gasoline (petrol) and diesel are formulated for engines and have properties that make them unsuitable and unsafe for cooking.