How does solubility affect boiling point?
The greater the solubility of a solute, the greater the boiling point.
Boiling point is a colligative property. It depends only on the numbers of particles in the solution, not on their identities.
The formula for boiling point elevation is
If we have two comparable compounds, the more soluble compound will have more particles in solution.
It will have a higher molality.
The boiling point elevation, and hence the boiling point, will be higher for the more soluble compound.