What is meant by abnormal molecular mass of solute? Discuss the factors which bring abnormallty in experimentally determined molecular masses of solutes using colligative properties.

Answer

The molecular mass obtained with the help of colligative property sometimes is different from normal molecular mass, it is called abnormal molecular mass. The factors which bring abnormallity are:
Association. When the solute particles undergo association, number of particles become less and molecular mass determined with the help of colligative property will be more.
Dissociation. It leads to increase in number of particles, therefore, increase in colligative property, therefore, decrease in molecular weight because colligative property in inversely proportional to molecular weight