What happens to crude oil during fractional distillation?

During fractional distillation, crude oil is heated to a boiling point where it vaporizes, and the vapors are then cooled and condensed back into liquid form. This process relies on the different boiling points of the various hydrocarbons present in crude oil. As the oil is heated, the lighter fractions vaporize at lower temperatures and rise through a column, while heavier fractions with higher boiling points remain in the liquid phase and are collected at the bottom.

The condensation occurs at different heights in the distillation column, allowing for the separation of the hydrocarbons into distinct fractions. These fractions can then be further processed and refined into useful products such as gasoline, diesel, and kerosene.

The other options do not accurately describe the key processes involved in fractional distillation. Filtering through sand, mixing with water, or freezing do not effectively separate components based on their boiling points, which is essential for the fractional distillation method. Thus, focusing on the boiling and condensing processes highlights the fundamental principle of fractional distillation in refining crude oil.