Catalysts lower activation energy without altering the Boltzmann distribution at constant temperature

Steps:

• The Boltzmann distribution shows the proportion of gas molecules with different energies at a fixed temperature.
• Activation energy (X) is the minimum energy barrier for reaction; only molecules above X react significantly.
• A catalyst lowers this barrier to a new, smaller value, allowing more molecules (those between old and new X) to react.
• The distribution curve and peak position remain unchanged since temperature is constant.

Why D is correct:

• Catalysts provide an alternative reaction pathway with reduced activation energy, as defined in transition state theory.

Why the others are wrong:

• A: The energy distribution is unchanged, so the number of high-energy particles stays the same.
• B: Peak shifts left only with decreased temperature, but temperature is fixed.
• C: Peak shifts right only with increased temperature, but temperature is fixed.

Final answer: D