Le Chatelier's Principle for Equilibrium Shifts Steps:

• Decreasing temperature increases product yield, so forward reaction must be exothermic (ΔH < 0) to favor products.
• Decreasing pressure increases product yield, so products must have more moles of gas than reactants to favor the side with more particles.
• Examine ΔH and gas moles for each option.
• Only option B has ΔH < 0 and more product moles (3 vs. 2).

Why B is correct:

• Exothermic forward reaction (ΔH = -226 kJ mol⁻¹) shifts right on cooling; more moles on right (3 vs. 2) shifts right on pressure decrease, per Le Chatelier's principle.

Why the others are wrong:

• A: Endothermic (ΔH > 0), so cooling decreases yield; fewer product moles (2 vs. 3), so pressure drop decreases yield.
• C: Exothermic (ΔH < 0), so cooling increases yield, but equal moles (2 vs. 2) means no pressure effect.
• D: Endothermic (ΔH > 0), so cooling decreases yield; more product moles (3 vs. 2) would increase yield on pressure drop, but temperature mismatches.

Final answer: B