Dissolving sodium chloride in water will

raise the freezing point of the sodium chloride
lower the freezing point of the sodium chloride
lower the freezing point of the solution
raise the freezing point of the solution

Some liquids can be distilled, but only at temperatures that are so high that it is impractical, or so high the compound decomposes. explain why distillation such compounds at significantly less than atmospheric pressure (some degree of vacuum) would solve this problem.