What is the boiling point of an aqueous solution of a nonelectrolyte that has an osmotic pressure of 10.50 atm at 25^$\circ$C K_b of water is 0.52^$\circ$C/m. Assume the density of the solution is the same as that of pure water. A) 0.22^$\circ$C B) 0.429^$\circ$C C) 99.78^$\circ$C D) 100.22^$\circ$C E) 100.43^$\circ$C

Question

Quizplus · Accepted Answer

First, we need to use the van't Hoff factor (i) to find the molar concentration of the solution. Since the solute is a nonelectrolyte, i = 1.
π = iMRT
10.50 atm = (1)(M/18.015 g/mol)(0.08206 L atm/mol K)(298 K)
M = 5.919 g/mol
Now we can use the equation for boiling point elevation:
ΔTb = Kb·m·i
where Kb is the molal boiling point constant for water (0.512 °C/m), m is the molal concentration of the solution, and i is again 1 for a nonelectrolyte.
ΔTb = (0.512 °C/m)(0.328 m)(1) = 0.168 °C
Therefore, the boiling point of the solution is:
100.00 °C + 0.168 °C = 100.168 °C
However, we need to convert the temperature to Celsius:
100.168 °C - 273.15 = 27.018 °C
And finally, we need to round to two decimal places:
27.02 °C
Therefore, the best answer is D: 100.22°C

What Is the Boiling Point of an Aqueous Solution of a Nonelectrolyte