At standard pressure, water boils at 100¬°C. Since the boiling point is defined as the point where the vapor pressure equals the atmospheric pressure, the vapor pressure in this situation must also be standard pressure (1 atm). The vapor pressure of the solvent in solution is therefore
Had the solution in the above problem not been at 100¬°C, its vapor pressure would have had to have been given in order to complete the problem. Note that the vapor pressure of the water is now less than 1 atm. A lower vapor pressure implies that the solvent has not yet reached its boiling point. In other words, the presence of calcium carbonate, a solute, has raised the boiling point of the solution.
