The experimental values of colligative properties of many solutes in solution resembles calculated values of colligative properties.
However in some cases, the experimental values of colligative properties differ widely than those obtained by calculations. Such experimental values of colligative properties are known as abnormal values of colligative properties. The causes for abnormal values of colligative properties are:
(i) Dissociation of solute: It increases the colligative properties.
e.g.: Dissociation of KCl, NaCl etc. in H2O.
(ii) Association of solute: It decreases the colligative properties.
e.g.: Dimerisation of acetic acid in benzene.
If the degree of dissociation of an electrolyte A2B3 is 25% in a solvent, then: