Extreme expansion and contraction is exhibited by clays such as montmorillonite, which have expanding lattices. Clays with nonexpanding lattices, such as kaolinite and chlorite, have very little capacity to shrink and swell. The exercises that follow contain a hypothesis relating to the concepts presented in the above discussion. Each hypothesis is followed by a simple experiment designed to test that hypothesis. The results of each experiment should be viewed qualitatively and evaluated as to whether they validate the hypothesis.
Soils are able to adsorb cations from the soil solution.
The amount adsorbed will be proportional to the amount of clay in the soil. Filter and save the extract. Pipet 2 ml of each extract into 2 clean test tubes. This will serve as a control. To each test tube add one drop of Reagent A and mix.