Which principle allows chromatography to separate the components of a mixture?

• A. Components are separated by applying an electric field to the mixture.
• B. Components are separated based on their boiling points.
• C. Separation occurs because all components react chemically with the stationary phase.
• D. Different components travel at different rates due to varying affinities for the stationary and mobile phases.

Answer: (D)

Verified step by step guidance

1. Understand that chromatography is a separation technique based on the distribution of components between two phases: a stationary phase and a mobile phase.
2. Recognize that components in a mixture have different affinities or interactions with the stationary phase (solid or liquid fixed in place) and the mobile phase (liquid or gas that moves).
3. Know that because of these varying affinities, different components travel through the stationary phase at different rates when carried by the mobile phase.
4. Realize that this difference in travel rates causes the components to separate spatially along the stationary phase, allowing for their identification or isolation.
5. Conclude that the principle behind chromatography is the differential migration of components due to their varying interactions with the stationary and mobile phases, not due to electric fields, boiling points, or chemical reactions with the stationary phase.