Gibbs free energy at constant pressure and temperature under equilibrium conditions is___________________?

Related Mcqs:

1. Gibbs free energy (G) is represented by, G = H – TS, whereas Helmholtz free energy, A. is given by, A = E – TS. Which of the following is the Gibbs-Helmholtz equation ?

   A. [∂(G/T)/∂T] = – (H/T2)
   B. [∂(A/T)/∂T]V = – E/T2
   C. Both A. and B.
   D. Neither A. nor B.

2. Gibbs free energy of mixing at constant pressure and temperature is always__________________?

   A. 0
   B. ∞
   C. + ve
   D. – ve

3. Gibbs free energy of a pure fluid approaches _____________ as the pressure tends to zero at constant temperature?

   A. Infinity
   B. Minus infinity
   C. Zero
   D. None of these

4. The change in Gibbs free energy for vaporisation of a pure substance is___________________?

   A. Positive
   B. Negative
   C. Zero
   D. May be positive or negative

5. Chemical potential (an intensive property) of a substance is a force that drives the chemical system to equilibrium and is equal to its partial molar properties. The ratio of chemical potential to free energy of a pure substance at constant temperature and pressure is________________?

   A. 0
   B. 1
   C. ∞
   D. None of these

6. The molar excess Gibbs free energy, gE, for a binary liquid mixture at T and P is given by, (gE/RT) = A . x1. x2, where A is a constant. The corresponding equation for ln y1, where y1 is the activity co-efficient of component 1, is__________________?

   A. A . x22
   B. Ax1
   C. Ax2
   D. Ax12

7. Consider the equilibrium A(g) + B(g) = AB(g). When the partial pressure of A is 10-2 atm, the partial pressure of B is 10-3 atm and the partial pressure of AB is 1 atm, the equilibrium constant ‘K’ is____________________?

   A. 10 atm-1
   B. 105 atm-1
   C. 10 (dimensionless)
   D. 105 (dimensionless)

8. Free energy, fugacity and activity co-efficient are all affected by change in the temperature. The fugacity co-efficient of a gas at constant pressure ______________ with the increase of reduced temperature?

   A. Decreases
   B. Increases
   C. Remains constant
   D. Decreases logarithmically

9. Gibbs-Duhem equation relates composition in liquid phase and the _____________ at constant temperature & pressure?

   A. Fugacity
   B. Partial pressure
   C. Activity co-efficient
   D. All (A), (B), and (C)

10. When liquid and vapour phases of one component system are in equilibrium (at a given temperature and pressure), the molar free energy is__________________?

    A. More in vapour phase
    B. More in liquid phase
    C. Same in both the phases
    D. Replaced by chemical potential which is more in vapour phase