Which of the following is true about solid-liquid equilibrium?Which of the following is true about solid-liquid equilibrium?

Question

A. The liquidus curve will be a straight line (like the bubble-point curve) when you assume an ideal solution for the liquid phase.
B. The melting point of all pure substances will decrease upon the addition of a second component.
C. Separation using crystallization is never preferred over distillation.
D. For solid-liquid equilibrium, the mixture fugacity coefficient of component i in the liquid phase must equal the mixture fugacity coefficient of component i in the solid phase.
E. None of the above are true.

Answer 1

A. Incorrect. Figure 13-17 shows the liquidus line is a curve, though examination of Equation 13.73 would also indicate the complexity of the relationship.
B. Incorrect. It depends on the type of solid solution that will occur upon mixing. For example, Figure 13-17 shows that when you add a little nickel to pure copper, the mixture melting point will increase.
C. Incorrect. Crystallization is the preferred separation method when substances have boiling points that are close to one another, such as some isomers.
D. Incorrect. The mixture fugacity of component i must be equal in the different phases, not the mixture fugacity coefficient.
E. Correct. None of the statements are true