Reversible And Irreversible Reaction MCQs

41. When a catalyst is added to a reversible reaction, it:

• A) Shifts equilibrium to the left
• B) Increases forward rate only
• C) Does not affect equilibrium position
• D) Stops the reaction
• Answer: C

42. The electrolysis of water is considered:

• A) A reversible process
• B) An irreversible process
• C) A redox equilibrium
• D) A dynamic process
• Answer: B

43. Which is not a characteristic of a reversible reaction?

• A) Formation of stable products only
• B) Occurs in closed systems
• C) Can reach dynamic equilibrium
• D) Forward and reverse rates become equal
• Answer: A

44. Reversible reactions generally require:

• A) Open systems
• B) High energy inputs
• C) Closed systems to maintain equilibrium
• D) Exothermic reactions only
• Answer: C

45. Combustion reactions are usually:

• A) Reversible
• B) Irreversible
• C) Endothermic
• D) Reversible with low reactants
• Answer: B

46. When products are not able to reform reactants, the reaction is:

• A) Reversible
• B) Exothermic
• C) Irreversible
• D) Catalytic
• Answer: C

47. A reversible reaction reaches equilibrium when:

• A) Reactants convert fully to products
• B) Rates of forward and reverse reactions equalize
• C) Reactants are replenished
• D) Temperature decreases
• Answer: B

48. Equilibrium constant (K) is relevant to:

• A) Irreversible reactions only
• B) Reversible reactions at equilibrium
• C) Open system reactions
• D) High-temperature reactions only
• Answer: B

49. An irreversible reaction can be driven by:

• A) Removal of products
• B) Addition of a catalyst
• C) Changes in reactant volume
• D) Fluctuations in ambient light
• Answer: A

50. In a chemical equation for a reversible reaction, the symbol used is:

• A) →
• B) ⇌
• C) ←
• D) ↔
• Answer: B