Calculating boiling point of a solution What is the boiling point of an aqueous solution that has a vapor pressure of $23.0~\text{Torr}$ at $25~^\circ\text{C}$?
$(P^\circ_{\ce{H2O}}=23.78~\text{Torr};~K_\mathrm b= 0.512~^\circ\mathrm{C\ kg/mol})$

To solve this I used the equation $\Delta T_\mathrm b =m\times K_\mathrm b$. I calculated a molality of $1.88247\ \mathrm{mol/kg}$ which I then used to calculate a boiling point of $-0.9638\ \mathrm{^\circ C}$. This answer is apparently wrong and I don't understand why.
If molality is 1.88, then the change in boiling point is -0.96 degrees C, not the boiling point itself.