Moderate

Addition of catalyst during a chemical reaction alters:

Correct answer: C. Ea (Activation Energy)

  • A. H (Enthalpy)
  • B. E (Energy of Reactants or Products)
  • C. Ea (Activation Energy)
  • D. Collision frequency

Explanation

The correct answer is Option C: Ea (Activation Energy). A catalyst functions by offering an alternative reaction pathway with a reduced activation energy, meaning the reaction can occur more readily. This does not affect the enthalpy (H), the energy of the reactants or products (E), or the collision frequency. The catalyst's role is purely in lowering the energy barrier (activation energy) that the reactants must overcome to transform into products, thereby increasing the reaction rate.

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About Reaction Kinetics

Reaction kinetics relates reaction rate to concentration, temperature, surface area and catalysts. Questions cover rate laws, reaction order, rate constants, activation energy and the activated complex, including how a catalyst lowers the activation energy without changing the overall energy change or equilibrium position.

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