Kc increases for endothermic reaction when temperature rises

Steps:

• Reaction is endothermic (ΔH = +58 kJ mol⁻¹), so forward direction absorbs heat.
• Kc rises from 1.5 × 10⁻³ to 1.7 × 10⁻³ mol dm⁻³, indicating shift toward products.
• Per Le Chatelier's principle, higher temperature favors endothermic direction, increasing Kc.
• Pressure changes do not alter Kc value, which depends only on temperature.

Why C is correct:

• Endothermic reactions have Kc that increases with temperature, as heat acts like a reactant (van't Hoff equation: ln K = -ΔH/RT + constant).

Why the others are wrong:

• A: Pressure increase shifts equilibrium left (fewer moles), but Kc remains unchanged at constant temperature.
• B: Pressure decrease shifts right, but Kc value is unaffected.
• D: Temperature decrease favors exothermic direction, decreasing Kc.

Final answer: C