Which type of distillation primarily focuses on the separation of liquids?

Fractional distillation is primarily focused on the separation of liquid mixtures based on differences in boiling points. This process is particularly effective when dealing with mixtures that have closely related boiling points, as it allows for a more precise separation. In fractional distillation, a fractionating column is used, which increases the surface area for vaporization and condensation, allowing for multiple cycles of evaporation and re-condensation. This results in a more refined separation of components compared to other distillation methods.

In contrast, batch distillation processes operate on smaller volumes and may not achieve as fine a separation in some cases, while continuous distillation maintains a constant feed and product output but can be less efficient for complex mixtures. Steam distillation primarily applies to heat-sensitive materials, typically in the extraction of essential oils, rather than the separation of liquid mixtures. Therefore, the focus of fractional distillation on separating liquids based on differing boiling points makes it the correct choice in this context.