20 Questions
What is the chemical formula of silica gel?
SiO2
How does the polarity of silica gel compare to alumina?
Silica gel is less polar than alumina.
What type of adsorbent is silica gel?
Acidic adsorbent
Which compounds does silica gel preferentially retain?
Basic compounds
What is the relationship between the polarity of silica gel and its adsorption properties?
The lower the polarity of silica gel, the better it can adsorb basic compounds.
What type of interactions does the compound exhibit?
Dipole-dipole and H-bonding
How do polar analytes interact with the stationary phase in TLC?
They interact strongly with the stationary phase
Why do polar analytes move very slowly up the TLC plate?
Due to strong interactions with the stationary phase
Which type of bonding is most likely responsible for the slow movement of polar analytes up the TLC plate?
Hydrogen bonding
What effect do dipole-dipole interactions have on the movement of polar analytes in TLC?
Slows down their movement
What are the 2 most common adsorbents used in chromatography?
Porous alumina and porous silica gel
Which material is NOT commonly used as an adsorbent in chromatography?
Activated charcoal
Which of the following is a common misconception about chromatography adsorbents?
Activated carbon is one of the 2 most common adsorbents
Why are porous alumina and porous silica gel commonly used as adsorbents in chromatography?
They provide a high surface area for adsorption
What is a key advantage of using porous alumina and porous silica gel in chromatography applications?
They provide good resolution due to their selectivity
Which statement is true about the mobile phase in thin-layer chromatography (TLC)?
The mobile phase is relatively nonpolar.
How do nonpolar analytes interact with the components of a TLC plate?
They interact weakly with the polar silica gel and strongly with the nonpolar mobile phase.
What happens to nonpolar analytes on a TLC plate?
They move higher up the TLC plate.
Which of the following is true about the interaction between analytes and the components of a TLC plate?
Polar analytes interact more strongly with the polar silica gel.
What is the purpose of using a relatively nonpolar mobile phase in TLC?
To increase the separation of nonpolar analytes on the TLC plate.
Learn about the types of stationary phases in chromatography, focusing on porous alumina and porous silica gel. These are the two most common adsorbents used in chromatography techniques.
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