What does the separation of substances in chromatography depend upon?

Chromatography is a technique used to separate mixtures of substances based on how they interact with different phases in the system. The correct answer focuses on the distribution of substances between the stationary phase (the material that does not move) and the mobile phase (the solvent that moves).

In chromatography, different substances will have varying affinities for the stationary and mobile phases. For example, a substance that interacts more strongly with the stationary phase will move more slowly, while one that interacts more with the mobile phase will travel faster. This differential distribution results in the separation of substances as they move through the chromatography medium.

Factors such as temperature or size can influence the speed of the chromatographic process, but they do not directly dictate the separation mechanism. Color, while visible during the process, does not play a critical role in determining how substances will separate either. The core principle underlying the effective separation of substances in chromatography is indeed based on how these substances distribute themselves between the stationary and mobile phases.