Question

A molecule X associates in a given solvent as per the following equation:
X ⇌ (X)_n
For a given concentration of X, the van’t Hoff factor was found to be 0.80 and the
fraction of associated molecules was 0.3. The correct value of ‘n’ is:

• A. 2
• B. 3
• C. 1
• D. 5

Answer 1

The Correct Option is B

\(\text{The van’t Hoff factor } i \text{ is related to the association factor } n \text{ by the formula:} \\ i = \frac{1}{n} \\ \text{Given that } i = 0.80, \text{ we can find the value of } n \text{ as follows:} \\ n = \frac{1}{0.80} = 1.25 \\ \text{Since the fraction of molecules associated is } 0.3, \text{ the remaining fraction that is unassociated is } 0.7. \\ \text{Therefore, } n = 3 \text{ is the correct value for the association factor.}\)