Which option correctly lists the order of fractions from top to bottom of the fractional column?

Which option correctly lists the order of fractions from top to bottom of the fractional column?

• A. Refinery gases, Gasoline, Kerosene, Diesel, Fuel oil, Bitumen
• B. Refinery gases, Kerosene, Gasoline, Diesel, Bitumen, Fuel oil
• C. Gasoline, Refinery gases, Kerosene, Diesel, Bitumen, Fuel oil
• D. Refinery gases, Gasoline, Diesel, Kerosene, Fuel oil, Bitumen

Answer: (A)

In a fractional distillation column, the separation happens by boiling point: lighter fractions with lower boiling points rise to the top, while heavier ones with higher boiling points stay lower and condense there. Refinery gases have the lowest boiling points, so they sit at the very top. Just below are gasoline, then kerosene, which needs a higher temperature to vaporize. Below kerosene is diesel, then fuel oil, and at the bottom the heaviest fraction, bitumen, which has the highest boiling point. This sequence—refinery gases, gasoline, kerosene, diesel, fuel oil, bitumen—reflects increasing boiling points from top to bottom.

In a fractional distillation column, the separation happens by boiling point: lighter fractions with lower boiling points rise to the top, while heavier ones with higher boiling points stay lower and condense there. Refinery gases have the lowest boiling points, so they sit at the very top. Just below are gasoline, then kerosene, which needs a higher temperature to vaporize. Below kerosene is diesel, then fuel oil, and at the bottom the heaviest fraction, bitumen, which has the highest boiling point. This sequence—refinery gases, gasoline, kerosene, diesel, fuel oil, bitumen—reflects increasing boiling points from top to bottom.