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Which of the following statements correctly describes the effect of a catalyst on the activation energy () of a reaction?

medium MCQ 2 marks Class 12 · Chemistry · Chemical Kinetics
  1. A catalyst increases the activation energy, making the reaction slower.
  2. A catalyst provides an alternative pathway with a lower activation energy, but does not change the overall enthalpy change of the reaction.
  3. A catalyst changes both the activation energy and the equilibrium constant of the reaction.
  4. A catalyst eliminates the activation energy altogether, allowing the reaction to occur spontaneously.
Answer
A catalyst provides an alternative pathway with a lower activation energy, but does not change the overall enthalpy change of the reaction.

Step-by-step solution

  1. Identify the role of a catalyst: it speeds up a reaction by offering a different reaction pathway.
  2. Recall that the alternative pathway has a lower maximum energy barrier, i.e., lower .
  3. Remember that a catalyst does not alter the thermodynamics; the enthalpy change of the overall reaction remains the same.
  4. Select the option that states the catalyst lowers while leaving unchanged.
Common mistake: Thinking a catalyst changes the overall enthalpy change of the reaction

Concept tested: Effect of catalyst on activation energy

Published · How this solution was prepared and checked

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