Question

Which is not a common way of carrying chromatography?
A.Spreading irregularly
B.Radial/ circular
C.Ascending
D.Descending

Answer 1

To solve this question, we must first discuss the different types of chromatography techniques that are there. Then, depending on the shortcomings of each of these techniques, we can determine the least common way of chromatography that is there.

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
Chromatography can be understood as a way to quickly and efficiently separate the components of the mixture and clean the compounds. It is based on the basic principle that different components of the mixture move through the stationary phase at different speeds. The options that are given to us can be discussed as follows
1.Descending: The chromatogram is developed by moving the solvent along the paper. Here the mobile phase is at the top of the solvent carrier. The stain is held on top and the solvent flows over the top of the paper.
2.Ascending: This is where the solvent moves up the chromatography paper. Organic and inorganic substances are separated using both these techniques of ascending and descending chromatography.
3.Radial: This is also known as circular chromatography. A circular filter paper is removed and the sample is placed in the centre of the paper. After the stain has dried, the filter paper is bound horizontally to a petri dish containing solvent so that the wick of the paper is immersed in the solvent. The solvent rises through the wick and the components are separated in concentric circles.
4.Irregular spreading: This is done by irregularly spreading the moving phase over the stationary phase. This causes a variation in the chromatography readings because the concentration of the mixture is varied over the tested two-dimensional surface. Because of this, irregular spreading is not preferred.

Hence, Option A is the correct option

Note: Another type of chromatography is Ascending-Descending Chromatography. This is a mixture of the two techniques mentioned above. The top of the ascending chromatography can be folded over a pen so that the paper can descend after it has passed through the rod.