For the exothermic reaction A + B ⇌ C + heat, what happens to the position of equilibrium when the temperature is increased?

For the exothermic reaction A + B ⇌ C + heat, what happens to the position of equilibrium when the temperature is increased?

• A. Shifts toward products (the exothermic direction).
• B. No shift occurs.
• C. The equilibrium constant becomes undefined.
• D. Shifts toward reactants (the endothermic direction).

Answer: (D)

Le Chatelier’s principle says a system at equilibrium shifts to counteract a disturbance. For this exothermic reaction, heat is produced on the product side. Increasing the temperature adds heat, so the system responds by favoring the direction that consumes heat—the endothermic direction (the reverse reaction). That shifts the equilibrium toward the reactants, increasing A and B and decreasing C. Consequently, the equilibrium constant also tends to decrease with higher temperature for an exothermic process.

Le Chatelier’s principle says a system at equilibrium shifts to counteract a disturbance. For this exothermic reaction, heat is produced on the product side. Increasing the temperature adds heat, so the system responds by favoring the direction that consumes heat—the endothermic direction (the reverse reaction). That shifts the equilibrium toward the reactants, increasing A and B and decreasing C. Consequently, the equilibrium constant also tends to decrease with higher temperature for an exothermic process.