What is the principle behind the process of distillation?

The principle behind the process of distillation is the separation of components in a mixture based on differences in their boiling points. When a liquid mixture is heated, the component with the lower boiling point vaporizes first. This vapor is then collected and cooled in a condenser, allowing it to return to the liquid state and be separated from the remaining components of the mixture.

This process is particularly effective for separating volatile substances from non-volatile substances or for separating two or more liquids with significant differences in their boiling points. For instance, in a simple distillation setup, if you have a mixture of water and ethanol, ethanol (which has a lower boiling point) will evaporate first, allowing it to be collected separately from water.

The other methods listed—separation based on densities, pH levels, or solubility—do not effectively describe the distillation process, as they involve different principles and techniques unrelated to the temperature-dependent phase change utilized in distillation.