What distinguishes simple distillation from fractional distillation?

The distinguishing factor between simple distillation and fractional distillation lies in their application based on the boiling points of the substances being separated. Simple distillation is particularly effective for separating components of a liquid mixture when there is a significant difference in boiling points, typically around 25 degrees Celsius or more. This significant difference allows for efficient separation, as the more volatile component vaporizes and can be condensed separately without significant interference from the less volatile component.

In contrast, fractional distillation is utilized for separating mixtures of liquids that have closer boiling points. In fractional distillation, a fractionating column is employed, which provides a larger surface area for multiple vaporization-condensation cycles, allowing for a more effective separation of components with minor differences in boiling points.

In summary, the correct answer emphasizes that simple distillation is best suited for liquids with significantly different boiling points, making it a fundamental technique in organic chemistry for purification processes, especially when the compounds involved are well-separated in terms of their volatility.