80g of NaCl are dissolved in 400g H2O. if the vapor pressure of the water is 40 mmHg , what is the vapor pressure of NaCl above the solution?
To find the mole fraction, calculate the number of moles of H20 and NaCl in solution, and divide the number of moles of H2O by the total number of moles. Since NaCl breaks up into two ions in solution, van Hoft's factor will equal two.
X=mole fraction of water
i=van hoft's factor=2
Plug in your values and solve the above equation.
posted by Devron