A system is said to be at equilibrium, if the entropy of the system has reached ____________ value?

Related Mcqs:

1. Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg. K, entropy of saturated vapour = 7.2234 kJ/kg. K) The exit condition of steam is_______________?

   A. Superheated vapour
   B. Partially condensed vapour with quality of 0.9
   C. Saturated vapour
   D. Partially condensed vapour with quality of 0.1

2. When a system is in equilibrium for all possible processes, the differential or finite change of entropy is__________________?

   A. < 0
   B. > 0
   C. = 0
   D. None of these

3. A solid metallic block weighing 5 kg has an initial temperature of 500°C. 40 kg of water initially at 25°C is contained in a perfectly insulated tank. The metallic block is brought into contact with water. Both of them come to equilibrium. Specific heat of block material is 0.4 kJ.kg-1. K-1. Ignoring the effect of expansion and contraction and also the heat capacity to tank, the total entropy change in kJ.kg-1, K-1 is_________________?

   A. -1.87
   B. 0
   C. 1.26
   D. 3.91

4. In which of the following reaction equilibrium, the value of equilibrium constant Kp will be more than is Kc ?

   A. 2HI ⇌ H2 + I2
   B. N2O4 ⇌ 2NO2
   C. 2SO2 + O2 ⇌ 2SO3
   D. None of these

5. Two substances are in equilibrium in a reversible chemical reaction. If the concentration of each substance is doubled, then the value of the equilibrium constant will be___________________?

   A. Same
   B. Doubled
   C. Halved
   D. One fourth of its original value

6. Entropy of a substance remains constant during a/an ____________ change?

   A. Reversible isothermal
   B. Irreversible isothermal
   C. Reversible adiabatic
   D. None of these

7. The reaction A (l) → R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The numbers of degrees of freedom are ?

   A. 1
   B. 2
   C. 3
   D. 0

8. “When a system in equilibrium is subjected to a change in temperature, pressure or concentration, the equilibrium is displaced in a direction which tends to undo the effect of the change.” This is called the_______________?

   A. Le-Chatelier principle
   B. Kopp’s rule
   C. Law of corresponding state
   D. Arrhenius hypothesis

9. 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)

10. During a reversible isothermal expansion of an ideal gas, the entropy change is_________________?

    A. +ve
    B. 0
    C. -ve
    D. ∞