# Solution: Determine the required concentration (in percent by mass) for an aqueous ethylene glycol (C2H6O2) solution to have a boiling point of 107.1 oC.

###### Problem

Determine the required concentration (in percent by mass) for an aqueous ethylene glycol (C2H6O2) solution to have a boiling point of 107.1 oC.

###### Solution

We’re being asked to calculate the mass percent of ethylene glycol (C2H6O2) solution to have a boiling point of 107.1 oC.

Recall that the boiling point of a solution is higher than that of the pure solvent and the change in boiling point (ΔT­b) is given by:

The change in boiling point is also related to the molality of the solution:

where:

i = van’t Hoff factor

m = molality of the solution (in m or mol/kg)

Kb = boiling point elevation constant (in ˚C/m)

Recall that the molality of a solution is given by:

We go through the following steps to solve:

Step 1. Calculate the molality

Step 2. Calculate the mass of solute and solvent

Step 3. Calculate the mass percent View Complete Written Solution