Which technique is used to separate components of a homogeneous mixture?

• A. Filtration
• B. Distillation
• C. Chromatography
• D. Decanting

Answer: (C)

Separating components of a homogeneous mixture requires exploiting differences in how each component interacts with a surface and with a solvent. Chromatography does exactly that: the mixture is carried by a mobile phase through or over a stationary phase, and each component distributes between the two phases based on its affinity. Because different substances interact differently with the stationary phase (and with the mobile phase), they travel at different speeds and end up in separate spots or fractions. This makes chromatography effective for solutions where all components are dissolved in the same phase, such as dyes in a solvent or pigments in ink.

Filtration and decanting rely on distinct physical phases or differences in particle size, which don’t exist in a true homogeneous solution, so they can’t separate dissolved components. Distillation separates by boiling point and works best for liquid mixtures; it can be limited when components have similar volatilities or form azeotropes. Chromatography, with its ability to separate a wide range of soluble components by differential interactions, is the most versatile choice for this scenario.