For a solute that dissociates in solution and one that associates, the van't Hoff factor i is respectively:
Agreater than 1 and less than 1
Bless than 1 and greater than 1
Cequal to 1 and equal to 1
Dgreater than 1 and greater than 1
Answer & Solution
Correct answer: A. greater than 1 and less than 1
1. Dissociation increases the number of particles, so observed colligative effect rises and i > 1 (e.g. KCl, i near 2).
2. Association decreases the number of particles, so i < 1 (e.g. ethanoic acid in benzene, i near 0.5).
3. Hence dissociation gives i > 1 and association gives i < 1.
_Source: NCERT Class 12 Chemistry Ch 1 "Solutions", p.23_
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