Why is it recommended to have a small amount (below the pencil line on the TLC plate) of eluent in the TLC chamber?Question 8Select one:spots will be washed off the TLC plateto avoid wastage of eluentto have concentrated eluent

The main reason for keeping the eluent level below the pencil line on the TLC plate is to prevent the spots from being washed off the plate.

Here's a step-by-step explanation:

1. The pencil line on the TLC plate is where the sample spots are placed.

2. If the level of the eluent (the solvent used in the process) in the TLC chamber is above this line, it would dissolve the spots as soon as the plate is placed in the chamber.

3. This would wash the spots off the plate, and they would travel with the solvent front. This would not only result in a loss of the sample, but it would also make it impossible to properly separate the components of the sample.

4. Therefore, to ensure that the spots remain on the plate and that the components of the sample are properly separated, it is recommended to keep the eluent level in the TLC chamber below the pencil line on the TLC plate.

The other options mentioned, such as avoiding wastage of eluent and having concentrated eluent, are not the primary reasons for this recommendation. While it is true that using less eluent can help save resources, the main purpose of keeping the eluent level low is to ensure proper separation of the sample components. Similarly, the concentration of the eluent does not directly affect the level of the eluent in the TLC chamber.