For each of the following dilute solutions, Van’t Hoff’s factor is equal of 3, except — Solutions and Colligative Properties Chemistry Question

💡 Solution & Explanation

Assuming 100% dissociation: $\text{Na}_2\text{SO}_4 \rightarrow 2\text{Na}^+ + \text{SO}_4^{2-}$ (3 ions); $\text{CaF}_2 \rightarrow \text{Ca}^{2+} + 2\text{F}^-$ (3 ions); $(\text{NH}_4)_2\text{CO}_3 \rightarrow 2\text{NH}_4^+ + \text{CO}_3^{2-}$ (3 ions); but $\text{K}_3\text{PO}_4 \rightarrow 3\text{K}^+ + \text{PO}_4^{3-}$ (4 ions, so $i=4$). Therefore, correct answer is C.