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

In a laboratory, Sophia is conducting an experiment to separate different compounds using adsorption chromatography. She is trying to understand the role of elutropic strength in her process. Which of the following statements is true about the role of elutropic strength in the adsorption 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

In a laboratory, Emma is conducting an experiment using adsorption chromatography to separate different compounds from a mixture. What is the main role of the stationary phase in this process?

• 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 a laboratory, Nora is conducting ion exchange chromatography to separate different ions in a solution. What is the primary basis for the separation of analytes?

• Molecular size

• Polarity

• Ionic charge

• Volatility

In a laboratory, Emma is trying to separate different compounds from a mixture. She is considering two methods: bonded-phase chromatography and liquid-liquid chromatography. Which of the following explains why Emma prefers bonded-phase chromatography 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

Aiden is conducting an experiment in his chemistry lab, and he needs to choose a solvent for a chromatography process on a silica stationary phase. He wants to select the solvent that has the highest elutropic strength. Which of the following solvents should he choose?

• 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