Experiment: Iodine in balance between two phases
Iodine is a black purplish solid.
In each test tube we see two not miscible liquids 1 et 2 .
In the first tube a small quantity of iodine is added.
In the second tube a bigger quantity of iodine is added.
The test tubes are shaken in order to establish equilibrium.
One observes the same ratio of intensities of coloration, therefore the same ratio of concentrations of $I_2$
Iodine is a black purplish solid.
