Law Of Equilibrium And Equilibrium Constant MCQs

31. Adding a catalyst to a reaction at equilibrium will:

• A) Shift the equilibrium to the right
• B) Shift the equilibrium to the left
• C) Increase the rate without affecting equilibrium
• D) Increase only the forward reaction rate
• Answer: C

32. The equilibrium constant for the reverse reaction is:

• A) Same as forward reaction
• B) Reciprocal of the forward reaction
• C) Product of forward reaction
• D) Half of forward reaction
• Answer: B

33. A very large equilibrium constant K implies:

• A) Almost complete reaction
• B) No reaction
• C) High concentration of reactants
• D) Low concentration of products
• Answer: A

34. In a homogeneous equilibrium, all species are in:

• A) Different phases
• B) The same phase
• C) Liquid phase only
• D) Gaseous phase only
• Answer: B

35. In a heterogeneous equilibrium, Kc expression includes:

• A) Only gases and aqueous species
• B) All species including solids
• C) Only liquids
• D) No species
• Answer: A

36. Increasing the pressure of a gaseous reaction at equilibrium will shift the reaction toward:

• A) The side with more moles of gas
• B) The side with fewer moles of gas
• C) The products only
• D) The reactants only
• Answer: B

37. If Kc for a reaction is less than 1, which is favored?

• A) Reactants
• B) Products
• C) Equally favored
• D) None
• Answer: A

38. What effect does adding an inert gas have on a reaction at equilibrium?

• A) Increases pressure, shifts equilibrium
• B) No effect on equilibrium
• C) Increases concentration of products
• D) Lowers activation energy
• Answer: B

39. The units of Kc for a reaction ( aA + bB \rightleftharpoons cC ) depend on:

• A) The coefficients a, b, and c
• B) The number of moles
• C) Temperature only
• D) Pressure only
• Answer: A

40. In a chemical equilibrium, which of the following will remain constant?

• A) Reaction rate
• B) Free energy
• C) Concentrations of reactants and products
• D) Both B and C
• Answer: D