Question

In adsorption chromatography mobile phase will be:
a.) Only solid
b.) Only liquid
c.) Only gas
d.) Liquid as well as gas

Answer 1

Hint: Chromatography is a technique used in the laboratory to separate the components of a mixture. Adsorption chromatography is based on the interaction of the adsorbate with the adsorbent. The mobile phase is generally a liquid (liquid-solid chromatography) or a gas (gas-solid chromatography).

Complete step by step answer:
To reach the solution, we require to learn the basics behind chromatography, especially focusing on adsorption chromatography.
Chromatography – It is a technique used in the laboratory to separate the components of a mixture.
Adsorption chromatography is one of the earliest techniques used in chromatography. It is based on the interaction of the adsorbate (the substance that is adsorbed) with the adsorbent (the substance that absorbs the adsorbate).
Now the components used in adsorption chromatography are a mixture, stationary phase, and moving phase.
Mixture - It is the mixture of all the substances that need to be separated.
Stationary phase – It is mostly a solid substance which absorbs the mixture and the mobile phase. It generally has a porous surface (example – cellulose).
Mobile phase – Mobile phase is mixed in with the mixture. The mobile phase is readily absorbed by the stationary phase and takes the components of the mixture with it. The mobile phase is generally a liquid (liquid-solid chromatography) or a gas (gas-solid chromatography).
Now, we know that the mobile phase carries the components of the mixture with it, but the components are absorbed by the stationary phase at different rates. Consider you are given a mixture with components A and B. Now A and B will be adsorbed on the stationary phase at different rates, thus we will see two different layers one representing substance A and one representing substance B.
Hence, the mobile phase can be either a gas or a liquid.
So, the correct answer is “Option D”.

Note: We mentioned that in adsorption chromatography, the mobile phase can be either a gas or a liquid. The choice depends on the situation, gas-solid chromatography is used when the compounds to be separated can be vaporized without decomposition or have low boiling points and liquid-solid chromatography is used when the sample is soluble in the mobile phase.