If two molecules associate to form one dimer and the degree of association is 60%, what is the van’t Hoff factor, i?
Answer and explanation
Correct answer: 0.70
When two molecules associate to form one dimer, the number of solute particles decreases. For dimerisation, the van’t Hoff factor is i = 1 − α/2, where α is the degree of association. With α = 60% = 0.60, i = 1 − 0.60/2 = 1 − 0.30 = 0.70. Therefore, association produces fewer particles and makes the colligative effect less than that of the non-associated solute.
Frequently asked questions
What is the correct answer to this question?
0.70
Why is this the correct answer?
When two molecules associate to form one dimer, the number of solute particles decreases. For dimerisation, the van’t Hoff factor is i = 1 − α/2, where α is the degree of association. With α = 60% = 0.60, i = 1 − 0.60/2 = 1 − 0.30 = 0.70. Therefore, association produces fewer particles and makes the colligative effect less than that of the non-associated solute.
Which subject and chapter does this question cover?
This is a Class 11 Chemistry question. Chapter: Chemical Bonding and Molecular Structure. Topic: Valence bond theory and hybridization.
