Pressure Effects on Rate and Yield in Haber Process Steps:

• Reaction is exothermic (ΔH negative), so decreasing temperature shifts equilibrium right (higher NH₃ yield) but slows rate by reducing kinetic energy.
• Increasing pressure shifts equilibrium right (fewer gas moles on product side) per Le Chatelier's principle, increasing yield; it also raises reactant concentrations, speeding up rate via more collisions.
• Increasing catalyst surface area provides more active sites, accelerating rate without altering equilibrium position or yield.
• No option D provided, so evaluate A–C only.

Why B is correct:

• Higher pressure increases both rate (higher concentration speeds collisions) and yield (Le Chatelier's principle favors fewer moles).

Why the others are wrong:

• A decreases rate while increasing yield.
• C increases rate but leaves yield unchanged (catalysts speed attainment of equilibrium, not position).

Final answer: B