The van't Hoff factor (i) for a solute that completely dissociates into n particles is:

For complete dissociation: i = **n** (e.g., KCl → K⁺ + Cl⁻ → i = 2 ideally; K₂SO₄ → 3 ions → i = 3). For association (e.g., dimerisation), i < 1.