31. Which statement is true regarding Le Chatelier’s principle and catalysts?

• A) Catalysts shift the position of equilibrium
• B) Catalysts do not affect the position of equilibrium
• C) Catalysts slow down the forward reaction
• D) Catalysts increase the yield of the reaction
• Answer: B

32. Which of the following changes will shift the equilibrium to the left in an exothermic reaction?

• A) Increasing temperature
• B) Decreasing temperature
• C) Increasing reactant concentration
• D) Removing products
• Answer: A

33. In the Haber process for ammonia synthesis, increasing the pressure favors:

• A) Formation of ammonia
• B) Formation of nitrogen
• C) Formation of hydrogen
• D) Dissociation of ammonia
• Answer: A

34. Le Chatelier’s principle predicts that increasing the volume of a gas-phase equilibrium will:

• A) Shift equilibrium towards the side with more moles of gas
• B) Shift equilibrium towards the side with fewer moles of gas
• C) Have no effect on equilibrium
• D) Increase the temperature
• Answer: A

35. For a reaction where the forward process is endothermic, decreasing the temperature will:

• A) Shift equilibrium towards the products
• B) Shift equilibrium towards the reactants
• C) Increase the rate of the forward reaction
• D) Have no effect
• Answer: B

36. When a chemical system is at equilibrium, the rates of the forward and reverse reactions are:

• A) Equal
• B) Different
• C) Constantly changing
• D) Zero
• Answer: A

37. Which of the following will not shift the equilibrium of a system?

• A) Increasing reactant concentration
• B) Changing temperature
• C) Adding a catalyst
• D) Changing pressure
• Answer: C

38. For the equilibrium reaction: 2SO₂ + O₂ ⇌ 2SO₃, increasing the pressure will:

• A) Shift equilibrium to the right
• B) Shift equilibrium to the left
• C) Have no effect
• D) Increase the concentration of SO₂
• Answer: A

39. If a reaction is exothermic, increasing the temperature will:

• A) Shift the equilibrium towards the products
• B) Shift the equilibrium towards the reactants
• C) Increase the yield of products
• D) Have no effect on equilibrium
• Answer: B

40. Le Chatelier’s principle states that a system at equilibrium will adjust to changes by:

• A) Increasing reactants
• B) Reducing products
• C) Minimizing the disturbance
• D) Maximizing the disturbance
• Answer: C