What is chromatography used for?

What is chromatography used for?

• A. To precipitate ions with silver nitrate.
• B. To test pH of solutions.
• C. To measure mass of ions in solution.
• D. To separate substances in a mixture based on differences in interactions with stationary and mobile phases.

Answer: (D)

Chromatography works by separating substances in a mixture based on how they interact with two phases: a stationary phase that stays in place and a mobile phase that moves through it. Each component in the mixture differentially sticks to the stationary phase and dissolves in the mobile phase. Those with a stronger attraction to the stationary phase move more slowly, while those that prefer the moving solvent travel faster. Over time, this causes the mixture to split into separate components, visible as distinct spots or bands, which can help identify the substances by comparing how far each has moved. Think of how ink from a marker can split into multiple colors on filter paper as the water (the mobile phase) carries different dye molecules at different speeds. In thin-layer chromatography, the same idea applies on a plate with a thin layer of solid; the relative distances each component travels give useful clues about what’s present. Other options describe different lab techniques: precipitating ions with silver nitrate tests for certain ions, testing pH measures acidity or basicity, and measuring mass quantifies weight rather than separating mixture components.

Chromatography works by separating substances in a mixture based on how they interact with two phases: a stationary phase that stays in place and a mobile phase that moves through it. Each component in the mixture differentially sticks to the stationary phase and dissolves in the mobile phase. Those with a stronger attraction to the stationary phase move more slowly, while those that prefer the moving solvent travel faster. Over time, this causes the mixture to split into separate components, visible as distinct spots or bands, which can help identify the substances by comparing how far each has moved.

Think of how ink from a marker can split into multiple colors on filter paper as the water (the mobile phase) carries different dye molecules at different speeds. In thin-layer chromatography, the same idea applies on a plate with a thin layer of solid; the relative distances each component travels give useful clues about what’s present.

Other options describe different lab techniques: precipitating ions with silver nitrate tests for certain ions, testing pH measures acidity or basicity, and measuring mass quantifies weight rather than separating mixture components.