Catalysts Reduce Activation Energy Without Altering Boltzmann Distribution

Steps:

• Boltzmann distribution shows the proportion of gas molecules with energies from 0 to high values at fixed temperature.
• Activation energy X is the threshold energy needed for reaction, marked on the distribution curve.
• A catalyst provides an alternative reaction pathway with lower activation energy but does not affect molecular energy distribution.
• At constant temperature, the curve stays the same, but the activation energy line shifts left to a lower value.

Why D is correct:

• Catalysts lower activation energy (Ea) per transition state theory, increasing reaction rate by allowing more molecules to surpass the reduced Ea threshold.

Why the others are wrong:

• A: Distribution unchanged, so particles with high E remain the same fraction.
• B: Peak position fixed by temperature; catalyst has no effect.
• C: Peak does not shift right; energy spread is temperature-dependent.

Final answer: D