(Some Questions denote their format. All questions are answered) 1. What is the purpose of using a stationary phase in chromatography? A. To separate molecules based on their interactions with the stationary phase B. To speed up the separation process C. To increase the volume of the sample D. To remove impurities from the sample Answer: A. The stationary phase in chromatography interacts with the molecules in the sample, causing them to separate based on their different interactions. 2. True or False: In gas chromatography, the mobile phase is a gas and the stationary phase is a liquid coated on a solid support. Answer: False. In gas chromatography, both the mobile and stationary phases are gases. 3. Which of the following is NOT a type of chromatography? A. Gas chromatography B. Liquid chromatography C. Paper chromatography D. Electrophoresis Answer: D. Electrophoresis is a technique used to separate charged molecules based on their mobility in an electric field, not based on interactions with a stationary phase. 4. What is the purpose of using a gradient elution in chromatography? A. To separate molecules based on their size B. To improve the resolution of peaks in the chromatogram C. To increase the speed of the separation process D. To increase the pressure in the chromatography column