An industrial process involves two competing elementary reactions that consume the same gaseous reactant R at 350 K.
Reaction E: R → P₁ Activation energy = 40 kJ·mol⁻¹
Reaction F: R → P₂ Activation energy = 75 kJ·mol⁻¹
A catalyst that selectively lowers the activation energy of Reaction F to 45 kJ·mol⁻¹ is introduced while leaving Reaction E unaffected. Concentrations of R are kept identical in all trials.
(a) Before the catalyst is added, predict which product, P₁ or P₂, forms faster at 350 K. Support your prediction with kinetic reasoning.
(b) After catalyst addition, determine which product now forms faster. Explain how the change in activation energy alters the competition between the two pathways.
(c) Suppose the temperature is subsequently decreased to 320 K with the catalyst still present. Discuss qualitatively how this temperature change affects the relative rates of the two reactions and hence the product distribution.
(d) The plant manager proposes doubling the pressure of gaseous R instead of using the catalyst, hoping for the same shift in product distribution. Evaluate this proposal, comparing the effectiveness of pressure increase versus catalysis for altering selectivity between Reaction E and Reaction F.