What happens when a non-volatile solute is added to a solvent?

When a non-volatile solute is added to a solvent, the boiling point of the solution increases, a phenomenon known as boiling point elevation. This occurs because the presence of solute particles in the solution disrupts the ability of solvent molecules to escape into the vapor phase. As a result, a higher temperature is required to provide the energy necessary for the solvent molecules to overcome the intermolecular forces holding them in the liquid phase.

Boiling point elevation can be quantitatively described by the equation:

ΔT_b = i * K_b * m

where ΔT_b is the change in boiling point, i is the van 't Hoff factor (which accounts for the number of particles the solute splits into), K_b is the ebullioscopic constant of the solvent, and m is the molality of the solution.

In scenarios with non-volatile solutes, other changes occur, such as a decrease in the vapor pressure of the solvent and a decrease in the freezing point (a phenomenon known as freezing point depression), but the key concept regarding boiling point is that it will always increase when a non-volatile solute is added.