CCLC 2024.2025

Which of the following is the main principle of adsorption chromatography?

• Partition of solutes between two liquid phases

• Adsorption of solutes on the surface of a solid phase

• Exchange of ions between the stationary phase and solutes

• Separation of solutes based on size differences

Which of the following statements is true about the role of elutropic strength in chromatography?

• Elutropic strength refers to the density of the stationary phase

• A mobile phase with higher elutropic strength will elute compounds slower

• A mobile phase with higher elutropic strength will elute compounds faster

• Elutropic strength affects the polarity of the stationary phase

In reverse-phase chromatography, which of the following factors would cause an increase in the retention time of a polar analyte?

• Decreasing the polarity of the mobile phase

• Increasing the flow rate of the mobile phase

• Using a shorter column

• Increasing the temperature

Which type of liquid chromatography separates molecules based on their ability to distribute between two immiscible phases?

• Adsorption chromatography

• Partition chromatography

• Ion exchange chromatography

• Size exclusion chromatography

What is the main role of the stationary phase in adsorption chromatography?

• It acts as a mobile carrier for analytes

• It provides a porous surface for solutes to partition

• It provides active sites for solute adsorption

• It serves as a liquid film on a solid support

In ion exchange chromatography, what is the primary basis for the separation of analytes?

• Molecular size

• Polarity

• Ionic charge

• Volatility

Which of the following explains why bonded-phase chromatography is preferred over liquid-liquid chromatography?

• Bonded-phase chromatography can use both gas and liquid mobile phases

• The stationary phase in bonded-phase chromatography does not dissolve in the mobile phase

• Bonded-phase chromatography avoids using a support matrix

• It allows for the separation of larger molecules

Which of the following solvents has the highest elutropic strength on a silica stationary phase?

• Hexane

• Carbon tetrachloride

• Methanol

• Toluene

What is the primary difference between normal-phase and reverse-phase chromatography?

• Normal-phase uses polar stationary phases, while reverse-phase uses nonpolar stationary phases

• Normal-phase uses nonpolar stationary phases, while reverse-phase uses polar stationary phases

• Normal-phase uses gas as the mobile phase, while reverse-phase uses liquid

• Normal-phase is used for small molecules, while reverse-phase is used for large molecules