Question

Which is not a colligative property in the following ?

• A. pH of the buffer solution
• B. Boiling point elevation
• C. Freezing point depression
• D. Vapour pressure lowering

Answer 1

The correct option is A pH of the buffer solution

Colligative properties are properties of solutions that are assumed to depend on the ratio of the number of solute particles to the number of solvent molecules in a solution and not on the type of chemical species present.

Hence, boiling point elevation, freezing point depression and lowering of vapour pressure are colligative properties. Whereas the pH of a buffer solution is not a colligative property because pH depends only upon the molar concentration of H+ ion not on their number of particles in it.