A solution contains 0.115 mol H2O and an unknown number of moles of sodium chloride. The vapor

Question:

A solution contains 0.115 mol H2O and an unknown number of moles of sodium chloride. The vapor pressure of the solution at 30 oC is 25.7 torr. The vapor pressure of pure water at this temperature is 31.8 torr. Calculate the number of moles of sodium chloride in the solution. (Remember that sodium chloride is a strong electrolyte.)