21. Le Chatelier’s principle predicts that decreasing the concentration of a product will:

• A) Shift the equilibrium towards the reactants
• B) Shift the equilibrium towards the products
• C) Have no effect on equilibrium
• D) Stop the reaction
• Answer: B

22. When pressure is increased in a reaction involving gases, Le Chatelier’s principle predicts the equilibrium will shift towards:

• A) The side with fewer moles of gas
• B) The side with more moles of gas
• C) Neither side
• D) Increased heat production
• Answer: A

23. Which of the following statements about Le Chatelier’s principle is true?

• A) It applies to irreversible reactions
• B) It applies only to closed systems
• C) It cannot predict the effect of catalysts
• D) It is only valid for gaseous systems
• Answer: B

24. For an exothermic reaction, lowering the temperature will:

• A) Shift the equilibrium to the right
• B) Shift the equilibrium to the left
• C) Have no effect on equilibrium
• D) Increase the forward reaction rate
• Answer: A

25. In a reversible chemical reaction, if the concentration of a product is increased, the equilibrium will:

• A) Shift to the right
• B) Shift to the left
• C) Remain the same
• D) Stop completely
• Answer: B

26. Le Chatelier’s principle is used to predict:

• A) The direction of shift in equilibrium
• B) The rate of reaction
• C) The amount of product formed
• D) The nature of products formed
• Answer: A

27. In a reaction where the number of moles of gas is equal on both sides, increasing pressure will:

• A) Shift the equilibrium to the right
• B) Shift the equilibrium to the left
• C) Have no effect on equilibrium
• D) Stop the reaction
• Answer: C

28. According to Le Chatelier’s principle, adding more reactants to a system at equilibrium will:

• A) Shift the equilibrium to the right
• B) Shift the equilibrium to the left
• C) Have no effect on equilibrium
• D) Lower the pressure
• Answer: A

29. In an endothermic reaction, increasing the temperature will cause the equilibrium to:

• A) Shift to the right
• B) Shift to the left
• C) Have no effect
• D) Stop the reaction
• Answer: A

30. The effect of temperature changes on equilibrium is significant for:

• A) Only endothermic reactions
• B) Only exothermic reactions
• C) Both endothermic and exothermic reactions
• D) Reactions involving solids only
• Answer: C