Which properties depend on the number of solute particles rather than their identity?

The correct answer highlights colligative properties, which are unique because they depend solely on the number of solute particles present in a solution, not on the type of particles. This means that whether the solute is salt, sugar, or another substance, as long as the same number of solute particles is present, the effects on the solution's properties will be similar.

Colligative properties include boiling point elevation, freezing point depression, vapor pressure lowering, and osmotic pressure. For example, adding more solute particles to a solvent results in a higher boiling point and a lower freezing point, regardless of the specific identity of the solute. This characteristic makes colligative properties particularly important in various chemical applications where the concentration of solute affects the behavior of solutions.

In contrast, thermodynamic properties relate to the energy changes and state functions in a system, kinetic properties deal with the speed and mechanism of reactions, and concentration properties generally describe the amount of solute in a given volume of solution, which can be influenced by solute identity. Thus, colligative properties stand out as those that are strictly a function of particle number, aligning perfectly with the question's criteria.