Which product is collected at the bottom of the fractional column during the fractional distillation of crude oil?

Which product is collected at the bottom of the fractional column during the fractional distillation of crude oil?

• A. Gasoline
• B. Kerosene
• C. Diesel
• D. Bitumen

Answer: (D)

Fractional distillation separates crude oil by boiling point: as the mixture is heated, lighter compounds rise and condense higher up the column, while the heaviest ones require much higher temperatures and stay toward the bottom as a residue. Bitumen is the heaviest, highest-boiling fraction, so it does not vaporize and remains at the bottom as a thick, sticky residue. Lighter fractions like gasoline, kerosene, and diesel boil at lower temperatures and are collected higher up in the column, which is why they are not found at the bottom.

Fractional distillation separates crude oil by boiling point: as the mixture is heated, lighter compounds rise and condense higher up the column, while the heaviest ones require much higher temperatures and stay toward the bottom as a residue. Bitumen is the heaviest, highest-boiling fraction, so it does not vaporize and remains at the bottom as a thick, sticky residue. Lighter fractions like gasoline, kerosene, and diesel boil at lower temperatures and are collected higher up in the column, which is why they are not found at the bottom.