Question

Why is the molecular mass determined by measuring the colligative property in case some solutes are abnormal?
(A) Due to association or dissociation of solute molecules
(B) Due to insolubility of solute molecules
(C) Due to decomposition of solute molecules
(D) Due to the large size of solute molecules

Answer 1

One of the simplest approaches for determining the molecular weight of diverse substances has been to use colligative properties of solution. Because the number of molecules of solute in a solution determines its colligative properties, this method is particularly useful for measuring the molar masses of complicated molecules, proteins, macromolecules, and polymers.

Complete answer:
Some properties of dilute solutions containing non-volatile solutes are dependent only on the number of solute particles present, not on the type of solute present. These are referred to as colligative qualities. These properties are particularly noticeable in dilute solutions.
The number of particles changes as a result of the association or dissociation of solute molecules. There is a shift in molecular mass because colligative qualities are dependent on the number of particles.
Hence, the correct option is A. Due to association or dissociation of solute molecules.

Note:
The four colligative properties that can be exhibited by a solution are: Boiling point elevation, Freezing point depression, Relative lowering of vapour pressure, Osmotic pressure. The word "colligative" was derived or taken from the Latin word "colligatus," which means "bound together."