question_answer

  Show graphically that the freezing point of a liquid will be depressed when non-volatile solute is dissolved in it. The freezing point of a solution containing 0.3 gm of acetic acid in 30.0 gm of benzene is lowered by 0.45°C. Calculate the Vant Hoff factor.                                                                                                                                                      5 ( for benzene = 5.12 )

Answer:

                  Figure explains diagrammatically the depression of freezing point of a liquid. is the freezing point of the pure liquid. EBA is the sublimation curve for the solid solvent.                       1 AD is the vapour pressure curve for pure liquid. The point at which these two curves meet is the freezing point of the pure liquid.                                                                                                                      2                                                                 Fig. : Depression of freezing point.   Numerical: Molality of solution:                                                                                                                                                       1                                                                                                                                                                 1