To find the boiling point of the water solution, we need to calculate the boiling point elevation using the formula:
∆Tb=i⋅Kb⋅mwhere:
∆Tb is the boiling point elevation,
i is the van 't Hoff factor, which is 1 for glucose as it does not dissociate in solution
Kb is the ebullioscopic constant for water, given as
0.52K‌kg‌mol−1,
m is the molality of the solution.
To calculate the molality
m, use:
m=‌| ‌ moles of solute ‌ |
| ‌ kilograms of solvent ‌ |
For glucose
(C6H12O6), with a mass of 180 g :
‌ Moles of glucose ‌=‌=1‌molThe solvent (water) is 1 kg :
m=‌=1‌mol∕kg Substituting into the formula for
∆Tb :
∆Tb=1×0.52×1=0.52KThe normal boiling point of pure water is 373.15 K . Therefore, the boiling point of the solution is:
Tb=373.15+0.52=373.67K