Basics of Chromatography

Chromatography is a physical method that is used to separate and analyze.....

• simple mixtures

• complex mixtures

• viscous mixtures

• metals

Answer explanation

Chromatography is a physical method that is used to separate complex mixtures. The mixture of different components is flushed through the system at different rates.

In which type of chromatography, the stationary phase held in a narrow tube and the mobile phase is forced through it under pressure?

• column chromatography

• planar chromatography

• liquid chromatography

Answer explanation

In Column chromatography, the stationary phase held in a narrow tube and the mobile phase is forced through it under pressure. It is carried out in a long glass column having a stop-cock near the bottom.

In chromatography, the stationary phase can be _____ supported on a solid.

• liquid or gas

• solid or liquid

• solid only

• liquid only

Answer explanation

In chromatography, there are two phases namely, stationary phase and mobile phase. The stationary phase can be solid or liquid supported on a solid.

In chromatography, which of the following can be mobile phase be made of?

• solid or liquid

• liquid or gas

• gas only

• liquid only

Answer explanation

In chromatography, the mobile phase can be composed of liquid or gas. It cannot be a solid material.

Chromatography cannot be used to purify volatile substances.

• True

• False

Answer explanation

Chromatography can be used to purify volatile substances if the carrier fluid, operating conditions and right adsorbent material are employed.

The retention factor is used to...

• zero the chromatography scale

• retain the solvent

• identify unknown compounds in a sample

• as a starting tool for chromatography

Answer explanation

Chromatography can be used to separate delicate products. This is because chromatography is not performed under severe conditions.

The Rf value for the blue component is..

• 0.3

• 0.7

• 10

• 3

Answer explanation

Use formula to calculate retention factor,

Rf = distance of solute traveled/ distance of solvent traveled.

Why must the base line in TLC be drawn in pencil and not pen?

• pencil is good at keeping substances in place

• pencil is soluble in water

• pencil is insoluble in water

• pencil is not colored

The substance in the mixture that has the greatest affinity for the mobile phase will travel...

• fastest

• slowest

A student extracts the color from some green smarties and uses paper chromatography to separate components colors. She finds blue has a Rf=0.38, and yellow Rf=0.75. This suggests...

• yellow is more strongly adsorbed onto the stationary phase and is less soluble in mobile phase.

• the yellow is more strongly adsorbed onto the stationary phase and is more soluble in the mobile phase.

• the blue is more strongly adsorbed onto the stationary phase and is less soluble in the mobile phase.

• the blue is more strongly adsorbed onto the stationary phase and is less soluble in the mobile phase.