Question

Which of the following statements about chromatography is correct?
A. Paper chromatography and gas chromatography are both routinely used for quantitative analysis only.
B. Paper chromatography is usually considered to be qualitative only, while gas chromatography can be qualitative or quantitative.
C. Paper chromatography and gas chromatography are both routinely used for qualitative analysis only.
D Paper chromatography is usually considered to be quantitative only, while gas chromatography can be qualitative or quantitative.

Answer 1

Hint: Chromatography is an important technique extensively used to separate mixtures into their components, purify compounds and also to test the purity of compounds. Now, we will see the definitions of partition chromatography and gas chromatography to get the answer.

Complete answer:
Partition Chromatography:
Partition chromatography is based on continuous differential partitioning of components of a mixture between stationary and mobile phases.
Paper chromatography is a type of partition chromatography. In paper chromatography, a special quality paper known as chromatography paper is used. Chromatography paper contains water trapped in it, which acts as the stationary phase.
A strip of chromatography paper spotted at the base with the solution of the mixture is suspended in a suitable solvent or a mixture of solvents (Fig. 12.13). This solvent acts as the mobile phase. The solvent rises up the paper by capillary action and flows over the spot. The paper selectively retains different components according to their differing partition in the two phases. It is used for quantitative analysis of organic compounds.
Whereas the gas chromatography is very sensitive and gives accurate results up to ppm. It has a gaseous mobile phase that is pumped through the column at constant pressure. Here the gas acts as a mobile phase whereas the column acts as a stationary phase. This technique is used for both quantitative and qualitative analysis. It is a fast technique but expensive one.

So, option D is correct.

Note:
Column chromatography involves separation of a mixture over a column of adsorbent (stationary phase) packed in a glass tube.Thin layer chromatography (TLC) is another type of adsorption chromatography, which involves separation of substances of a mixture over a thin layer of an adsorbent coated on a glass plate.