8. Physical and Chemical Equilibrium

2 & 3 Marks

1. What are Reversible reactions? Give examples.

2. If there is no change in concentration, why is the equilibrium state considered dynamic?

3. What is Physical equilibrium?

4. Give examples for Physical equilibrium.

5. Explain - Solid - Liquid equilibrium.

6. Explain - Liquid - Vapour equilibrium.

7. Explain - Solid - Vapour equilibrium.

8. Explain - Solid in liquid equilibrium.

9. Explain - Gas in liquid equilibrium.

10. What is Melting point? Or What is Freezing point?

11. What is Boiling point? Or What is Condensation point of liquid?

12. Chemical equilibrium is also known as Dynamic equilibrium. Why?

13. What is a Homogeneous equilibrium? Give example.

14. What is a Heterogeneous equilibrium? Give example.

15. State Law of mass action.

16. What is Equilibrium constant?

17. What is the relation between KP and Kc? Give examples for which KP is equal to Kc.

18. Give examples for which KP is Greater than Kc.

19. Give examples for which KP is Less than Kc.

20. What happens when Δng = 0, Δng = – ve, Δng = + ve in a gaseous reaction?

21. For a gaseous homogeneous reaction at equilibrium, number of moles of products are Greater than the number of moles of reactants. Is Kc is larger or smaller than KP?

22. For a gaseous homogeneous reaction at equilibrium, number of moles of products are Less than the number of moles of reactants. Is Kc is larger or smaller than KP?

23. Write a Balanced chemical equation for an equilibrium reaction for which the equilibrium constant is given by expression Kc = [NH3]4 [O2]5 / [NO]4 [H2O]6.

24. Write the Kp and Kc for the following reactions :

      1) 2SO2(g) + O2(g) ⇌ 2SO3(g)                                        2) 2CO(g) ⇌ CO2(g) + C(s)

      3) Ag2O(s) + 2NH3(aq) ⇌ 2AgNO3(aq) + H2O(l)   4) CaCO3(s) ⇌ CaO(s) + CO2(g)

      5) CO2(g) + H2O(l) ⇌ H+(aq) + HCO3–(aq)

25. What is Reaction Quotient ‘Q’? Or Define - Reaction Quotient.

26. How is Reaction Quotient related to Equilibrium constant?

27. For a given reaction at a particular temperature, the equilibrium constant has constant value. Is the value of Q also constant? Explain.

28. When the numerical value of the Reaction Quotient (Q) is Greater than the Equilibrium constant (K), in which direction does the reaction proceed to reach equilibrium?

29. When the numerical value of the Reaction Quotient (Q) is Less than the Equilibrium constant (K), in which direction does the reaction proceed to reach equilibrium?

30. State Le-Chatelier principle.

31. Mention the factors that affect equilibrium.

32. Explain the effect of Concentration on a system at equilibrium.

33. Explain the effect of Pressure on a system at equilibrium.

34. Explain the effect of Temperature on a system at equilibrium.

35. Explain the effect of Catalyst on a system at equilibrium. Or

      What is the effect of Catalyst on the reaction at equilibrium?

36. Explain the effect of Inert gas on a system at equilibrium. Or

      What is the effect of added Inert gas on the reaction at equilibrium?

37. What are the conditions for getting maximum yield of SO3 by Contact Process?

38. What are the conditions for getting maximum yield of Ammonia by Haber’s Process?

39. Consider the following reactions, a) H2(g) + I2(g) ⇌ 2HI

b) CaCO3 (s) ⇌ CaO(s) + CO2(g)

c) S(s) + 3F2(g) ⇌ SF6(g). In each of the above reaction find out whether you have to increase (or) decrease the volume to increase the yield of the product.

5 Marks

1. Derive the relation between KP and Kc Or Deduce the expression for equilibrium constants Kc and KP. Or Derive the relation Kp = Kc(RT)Δng for a general chemical equilibrium reaction.

2. What is the relationship between formation Equilibrium constant and Dissociation constant? Give one example.

3. Consider the following equilibrium reactions and relate their equilibrium constants

    i) N2 + O2 ⇌ 2NO ;  K1     ii) 2NO + O2 ⇌ 2NO2 ; K2     iii) N2 + 2O2 ⇌ 2NO2 ;K3

4. Write the Applications of Equilibrium constant.

5. How will you predict the extent of reaction using equilibrium constant?

6. Explain how will you predict the direction of an equilibrium reaction.

7. Derive the KP and Kc relationship for H2(g) + I2(g) ⇌ 2HI  Or

    Derive the KP and Kc relationship for the formation of HI.

8. Derive the KP and Kc relationship for Dissociation of PCl5 Or

    Derive the KP and Kc relationship for PCl5(g) ⇌ PCl3(g) + Cl2(g).

9. Derive a general expression for the equilibrium constant KP and Kc for the reaction

    3H2(g) + N2(g) ⇌ 2NH3(g).  Or 

    Derive the KP and Kc relationship for N2(g) + 3H2(g) ⇌ 2NH3(g) Or

    Derive the KP and Kc relationship for Synthesis of Ammonia.

10. Apply Le-Chatelier’s Principle for the synthesis of Ammonia by Haber’s Process.

11. Apply Le-Chatelier’s Principle for the formation of HI.

12. Apply Le-Chatelier’s Principle for the synthesis of SO3 by Contact Process.

13. Derive Differential form of Van’t Hoff equation.

14. Derive Integral form of Van’t Hoff equation. Or Deduce / Derive the Van’t Hoff equation.

    Problems ∆ng, Equilibrium concentration, Kc, Partial pressures, Kp, ΔH° for the reaction, ΔH.