text: a. The presence of a non-volatile solute causes a decrease in the vapor pressure of the solvent. The magnitude of the decrease is directly proportional to the concentration of solute, expressed as the mole fraction:\nΔPvap = Xsolute P°vap\nwhere P°vap is the vapor pressure of the pure solvent.\n\nb. The presence of a non-volatile solute causes the solvent to freeze at a lower temperature than normal. The magnitude of the freezing point depression is directly proportional to the molality of solute:\nΔTf = Kf*m\nKf  is called the freezing point depression constant of the solvent.\n\nc. Similarly, a non-volatile solute causes the solvent to boil at a higher temperature. The magnitude of the so-called boiling point elevation is directly proportional to the concentration of solute, expressed as the molality, m:\nΔTb = Kb*m\nKb is called the boiling point elevation constant of the solvent.\n\nHope this helps,\nUltimeaciax