Catalyst alters reaction rate

Steps:

• Examine the diagram: Experiment 2 shows faster R production than experiment 1.
• Identify rate-affecting factors for gaseous reactants: pressure, catalyst, product removal.
• Rule out pressure: Lower pressure reduces reactant concentration, slowing rate.
• Rule out product removal: Continuous S removal shifts equilibrium but not initial kinetics.
• Conclude catalyst change: Explains increased rate without altering stoichiometry.

Why B is correct:

• Catalysts lower activation energy, providing a faster reaction pathway per transition state theory.

Why the others are wrong:

• A: Lower pressure decreases partial pressures of P and Q, reducing collision frequency and rate.
• C: Removing S(l) influences equilibrium via Le Chatelier's principle but does not accelerate the forward rate constant.

Final answer: B