Question

Why do colligative properties depend on the number of particles?

Answer 1

Colligative characteristics are those of a solution that are determined by the ratio of the number of solute particles to the number of solvent particles in the solution, rather than the chemical species present. The number ratio can be linked to several concentration units for a solution, such as molarity, molality, normalcy (chemistry), and so on.

Complete answer:
For dilute actual solutions, the assumption that solution characteristics are independent of the type of solute particles is merely approximate. Colligative properties, on the other hand, are a collection of solution qualities that may be fairly approximated if the solution is perfect. Only characteristics resulting from nonvolatile solute dissolution in a volatile liquid solvent are examined.
They are essentially solvent characteristics that are altered when a solute is present. Because the solute particles displace some solvent molecules in the liquid phase, lowering the solvent concentration, the colligative characteristics are unaffected by the solute's composition.
The following are some of the colligative characteristics.
Raoult's law describes a relative decrease in vapour pressure.
Boiling point is raised.
The freezing point has dropped.
Osmotic pressure is a term used to describe the amount of water in a
All colligative characteristics are inversely proportional to solute molar mass for a particular solute-solvent mass ratio.
Measurement of colligative characteristics for a dilute solution of a non-ionized solute like as urea or glucose in water or another solvent can lead to relative molar mass measurements, both for tiny molecules and polymers that are difficult to study otherwise. Measurements of ionised solutes, on the other hand, can be used to estimate the proportion of dissociation taking place.

Note:
Colligative characteristics are typically investigated in dilute solutions, whose behaviour can be compared to that of an ideal solution. In reality, the freezing point depression, boiling point elevation, vapour pressure elevation or depression, and osmotic pressure are all dependent on the chemical composition of the solvent and the solute at greater concentrations.