Pressure boosts gas reaction rates; catalysts lower activation energy

Steps:

• Identify reaction type: Two gases forming one product means gaseous reactants, so increasing pressure raises concentration.
• Apply collision theory: Higher pressure increases molecule collisions, speeding up the rate.
• Recognize platinum's role: As a catalyst, it provides an alternative pathway with lower activation energy (Ea).
• Match to options: Rate increases from pressure; Ea decreases from catalyst.

Why C is correct:

• For gas-phase reactions, pressure increases rate by Le Chatelier's principle and higher collision frequency; catalysts like platinum lower Ea per Arrhenius equation.

Why the others are wrong:

• A and B: Pressure increases, not decreases, rate for gases.
• D: Catalysts decrease, not increase, Ea.

Final answer: C