Two beakers are placed in a sealed box at 25 °C. One beaker contains 30.0 mL of a 0.050 M aqueous solution of a nonvolatile nonelectrolyte. The other beaker contains 30.0 mL of a 0.035 M aqueous solution of NaCl. The water vapor from the two solutions reaches equilibrium. (a) In which beaker does the solution level rise, and in which one does it fall?

Video transcript

Hey everyone we're told at 25 degrees Celsius two beakers were placed in a vacuum beaker a has 40 mL of 0. moller acquia solution of potassium bromide be Kirby has mL of 0.65 molar solution of a non volatile non electrolyte. Both solutions in the beakers were allowed to reach equilibrium, identify the beaker that will have a rise in solution level. So initially the morality and the volume of our two solutions are the same, but they differ in our van Hoff number. For our non electrolyte solution, Our Van Hoff Number is going to be one. While for potassium bromide, our van Hoff number is going to be too. Now when we calculate our particle concentrations for a non electrolyte, it will be 0.065 moller. While for potassium bromide we're going to get our two and multiply it by 0.045 moller which will get us to 0. moller. And these will be our particle concentrations for both. Now let's go ahead and bring up a drawing. So we can visualize this a little bit better with these values. We can see that potassium bromide has a lower vapor pressure than our non electrolyte solution. As a result the solvent of a non electrolyte solution has a higher tendency to escape or vaporize since the concentration of our potassium bromide solution is much greater. So our solvent will diffuse from the non electrolyte solution, which is less concentrated as we can see in our figure. The vaporized water has a higher attraction to the potassium bromide solution and it will condense back to this solution. So after equilibrium is achieved, The beaker be solution level will fall, which can be seen right here in our second diagram, While our beaker a solution will rise, which can be seen right here as well in our 2nd diagram. So to answer this question, the solution level of beaker B will fall while the solution of beaker A will rise. And this is going to be our final answer now. I hope that made sense and let us know if you have any questions.