(i) At the beginning of the experiment, why must the spot of indicator be above (ascending method) or below (descending method) the water level?
Answers
Answer:
The descending technique is a complex setup. This is built due to its time consuming ability. This develops along the gravity. Thus there is a force which will make the separation quick and easy. The filter paper is attached to a paper support. And the developing solvent (mobile phase) is filled into a chamber. The filter paper is saturated with the stationary phase before it is hung.
The mobile phase will gradually move downwards carrying the spot of the test sample along the paper. The term descending is given because the separation or the development of the chromatogram is taking place towards down. In this technique most polar substance will be on the top with respect to the tank where as the least polar ones will be at the bottom.