Raoult's law states that the vapor pressure of a solvent in a solution is equal to the mole fraction of the solvent multiplied by the vapor pressure of the pure solvent. In this case, we are given the vapor pressure of pure water 25 Torr and the mole fraction of NaCl 0.2 . We need to find the boiling point of the NaCl solution.First, we need to find the mole fraction of water in the solution. Since there are only two components in the solution NaCl and water , the mole fractions of NaCl and water must add up to 1:Mole fraction of water = 1 - Mole fraction of NaClMole fraction of water = 1 - 0.2Mole fraction of water = 0.8Now we can apply Raoult's law to find the vapor pressure of water in the NaCl solution:Vapor pressure of water in solution = Mole fraction of water Vapor pressure of pure waterVapor pressure of water in solution = 0.8 25 TorrVapor pressure of water in solution = 20 TorrThe boiling point of a solution occurs when the vapor pressure of the solution equals the atmospheric pressure. Assuming the atmospheric pressure is 760 Torr, we can set up a proportion to find the boiling point of the NaCl solution:Vapor pressure of pure water / Normal boiling point of water = Vapor pressure of water in solution / Boiling point of NaCl solutionWe know the vapor pressure of pure water is 25 Torr, the normal boiling point of water is 100C, and the vapor pressure of water in the NaCl solution is 20 Torr:25 Torr / 100C = 20 Torr / Boiling point of NaCl solutionNow we can solve for the boiling point of the NaCl solution:Boiling point of NaCl solution = 20 Torr 100C / 25 TorrBoiling point of NaCl solution = 2000 / 25Boiling point of NaCl solution 80CSo, the boiling point of the sodium chloride solution is approximately 80C.