text: what effect does the presence of a nonvolatile solute have upon? a/ the vapor pressure of a solution b/ the freezing point c/ the boiling point 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: δpvap = xsolute p°vap where p°vap is the vapor pressure of the pure solvent.  b. 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: δtf = kf*m kf  is called the freezing point depression constant of the solvent.  c. 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: δtb = kb*m kb is called the boiling point elevation constant of the solvent.  hope this helps, ultimeaciax