Equilibrium State MCQs

11. At equilibrium, which of the following is true for a reversible reaction?

• A) Reactants are completely converted into products
• B) Forward reaction rate equals the reverse reaction rate
• C) Products are completely converted into reactants
• D) Reactants stop converting into products
• Answer: B

12. In a chemical equilibrium, the concentrations of reactants and products:

• A) Continuously change
• B) Become zero
• C) Are equal
• D) Remain constant
• Answer: D

13. Which of the following best defines equilibrium in a chemical reaction?

• A) Only products are present
• B) Only reactants are present
• C) Rate of forward and reverse reactions are equal
• D) Reaction stops completely
• Answer: C

14. The equilibrium constant (K) of a reaction depends on:

• A) Concentrations of reactants and products
• B) Temperature
• C) Pressure
• D) Catalyst
• Answer: B

15. At equilibrium, the ratio of product concentration to reactant concentration is:

• A) Always equal to 1
• B) Dependent on temperature
• C) Constant at any conditions
• D) Always less than 1
• Answer: B

16. A large value of the equilibrium constant K indicates:

• A) High concentration of reactants
• B) High concentration of products
• C) Equal concentration of reactants and products
• D) Reaction does not proceed
• Answer: B

17. The equilibrium position of a reaction can be shifted by changing the:

• A) Catalyst
• B) Temperature
• C) Color of the reaction vessel
• D) Reaction mechanism
• Answer: B

18. In a dynamic equilibrium, molecules are:

• A) Static and unchanging
• B) Constantly interconverting
• C) Destroyed in the process
• D) At maximum energy
• Answer: B

19. If an equilibrium reaction has an equal number of moles of gas on both sides, changing the pressure will:

• A) Shift the equilibrium to the right
• B) Shift the equilibrium to the left
• C) Not affect the equilibrium
• D) Double the equilibrium constant
• Answer: C

20. Le Chatelier’s Principle helps predict the effect of changes on:

• A) Rate of reaction
• B) Activation energy
• C) Equilibrium position
• D) Molecular structure
• Answer: C