Another type of exchange reaction which has yielded surprising results is the rate of exchange of electrons between different valency states of the same element in the same solution. One might expect an almost instantaneous exchange equilibrium to be set up. This appears to be so for cerium 3 and cerium 4. One of the largest research areas in which radioisotopes have been used in chemistry is in the study of reaction mechanisms. Whether they be reactions involving large organic molecules, e.g. steroids or the relatively more simple reactions involving inorganic complex ions, the choice of a suitable radioisotopes as a tracer can provide unambiguous information concerning reaction pathways.
Tracers can also provide information on the efficiency and effectiveness of separation procedures.
Radioactive tracers can also be used in fairly conventional types of analysis such as, for example, to define an end point as in the cobalt titration experiment and for estimating accurately extremely small quantities or concentrations of substances as illustrated in the experiment on the measurement of solubility product of lead iodide. When you have rewound this tape, attempt the two experiments on tracer applications.