Which of the following statements is true?

Question

A. For the benzene + toluene system, the activity coefficient values for both components across all compositions will be close to 1.
B. The infinite dilution activity coefficient values for a mixture behaving according to the ideal solution must be zero.
C. The excess molar Gibbs free energy, divided by RT, is equal to the sum of the activity coefficient values, weighted by their mole fraction.
D. Another statement of the chemical equilibrium condition for mixtures in phase equilibrium says that the mixture fugacity coefficient of component i must have the same value in all of the phases that are in equilibrium.
E. None of the above are true.

Answer 1

A. Correct. These substances are very similar (size and intermolecular interactions), so deviations from ideal solution behavior will be minimal (? ? 1).
B. Incorrect. The natural logarithm of the infinite dilution activity coefficient must be zero, however.
C. Incorrect. It is equal to the sum of the natural logarithm of the activity coefficients, weighted by their mole fractions. See Equation 11.74 for this.
D. Incorrect. The fugacity coefficients must be weighted by their mole fractions, as shown in Equation 11.55.
E. Incorrect. One statement is true.