You can get the concept of: Law of proportions of chemical reactions, conductivity.
Principle: Alkylated halide show rapid exchange reaction of halogen in the corresponding solvents. These reactions are, respectively, replacing the so-called mechanism of SN2. This can be checked by measuring the conductivity, if the number of carriers is changed during the reaction. We investigate the change in conductivity during the reaction of propyl bromide with sodium iodide reaction (Finkelstein). With the calibration curve can be determined, the concentration of sodium iodide.
