Final answer:
The van't Hoff factor for benzoic acid is 1 because in lauric acid, it does not ionize and each molecule contributes only one particle in the solution.
Step-by-step explanation:
The van't Hoff factor for benzoic acid, when dissolved in lauric acid where it does not ionize at all, would be 1. Since the molecules of benzoic acid remain intact and do not ionize to produce more particles in solution, each molecule contributes to only one particle in the solution.
Therefore, the van't Hoff factor, which represents the number of particles formed in solution per formula unit of solute, is 1.