question: Q:Solvents A and B form an ideal solution. Solvent A has a vapor pressure of 345 torr at room temperature. At the same temperature, solvent B has a vapor pressure of 213 torr. What is the vapor pressure of a mixture where the mole fraction of A is 0.285?? 
  A:213 torr;B:345 torr;C:568 torr;D:251 torr