What effect will the following factors have on a chromatographic separation

Question

1) too strong an absorbent
2)collection of large elution fractions

Answer 1

1) various effects depending on adsorbent.
If too strong one or all materials may not be desorbed from the stationary phase at all.
One or all materials may tail so that there is either no complete separation or a large volume of solvent is needed to recover the wanted material.
Some strongly binding absorbents may result in rearrangement/degradation of the compound due to the long retention time (strongly acidic silica or basic alumina are frequent culprits).

2)
Large fractions might mean that there is no separation of material between fractions. Large fractions may also mean that much more time is needed to evaporate the solvent than would be needed if the compond was in a small number of small fractions.