Question

What are colligative properties useful for?

(a) Determining boiling and melting temperature

(b) Determining molar mass

(c) Determining equivalent weight

(d) Determining van’t Hoff factor

The question was posed to me in a national level competition.

I'm obligated to ask this question of Colligative Properties and Determination of Molar Mass in section Solutions of Chemistry – Class 12

Answer 1

Correct answer is (b) Determining molar mass

The explanation is: Colligative properties serve the purpose for determining molar masses of unknown compounds. Colligative properties are not used to determine boiling and melting temperatures as it would result in an incorrect value upon the addition of a solute. Equivalent weight can only be determined if the molar mass is known and the van’t Hoff factor is determined in a similar manner.