Catalysts accelerate reactions without altering yield

Steps:

• Catalysts lower activation energy, speeding up the reaction rate.
• The decomposition equation shows fixed stoichiometry: 2 mol H₂O₂ produce 1 mol O₂.
• Adding MnO₂ increases reaction speed, so O₂ evolves faster.
• Total O₂ volume remains the same, but collection is quicker.

Why D is correct:

• Catalysts increase reaction rate by providing alternative pathway with lower activation energy, per collision theory.

Why the others are wrong:

• A: Catalysts decrease, not increase, activation energy.
• B: Catalysts are regenerated, not consumed.
• C: Yield (total O₂) is unchanged; only rate increases.

Final answer: D