Boiling Point Elevation Molality $m = \; \frac{x}{W} \times 1000$ .....(i) Where, Molality $= m$ Number of mole of solute $= x$ Weight of solvent in grams $= W$ Moles of solute $=$ mass of solute $/$ molar mass of solute From eq. (i), (ii), (iii), we derive that elevation of boiling point is inversely proportional to the molar mass of the solute.