The van't Hoff factor, which can be calculated from freezing depression measurements, can be used to study the effect of ion-pair formation in inorganic salts. We studied the effect of ion-pair formation in a systematic way by varying the size of the cation from lithium to potassium as well as the change of the ion charge from +1 to +3 using various metal ions. Increasing the charge and reducing the size of the ion results in a lower degree of dissociation in accordance to the theory. The basic theory behind these experiments is covered in the General Chemistry I courses while the experimental setup costs are very low and the data collection and time spent are minimal. Both the results and challenges in adopting this experiment in an undergraduate laboratory are presented.