Question

Abnormal colligative properties are observed only when the dissolved non-volatile solute in a given dilute solution

• A. is a non-electrolyte
• B. offers an intense colour
• C. associates and dissociates
• D. offers no colour

Hint:

When studying colligative properties, remember that the key factor is the number of particles in solution. Association or dissociation of solute particles can lead to deviations from expected behaviour.

Answer 1

The Correct Option is C

Abnormal colligative properties, such as depression of freezing point or elevation of boiling point, are observed in solutions where solutes dissociate or associate in non-ideal ways. 
The dissociation or association of solute particles can change the expected effect on colligative properties, leading to abnormal behaviour. 
For example, certain solutes might ionize or form complexes that alter the number of effective particles in solution, which is why the abnormal properties arise.