For an exothermic reaction, an increase in temperature will:

• A. decrease the equilibrium constant
• B. increase the equilibrium constant
• C. cause the reaction to shift toward the products
• D. have no effect on the equilibrium constant

Answer: (A)

Verified step by step guidance

1. Recall Le Chatelier's Principle, which states that if a system at equilibrium is disturbed, the system will adjust to counteract the disturbance.
2. Understand that for an exothermic reaction, heat is released as a product, so heat can be considered as a product in the equilibrium expression.
3. When temperature increases, the system will try to absorb the excess heat by shifting the equilibrium position to the left (toward the reactants) to reduce the added heat.
4. Since the reaction shifts toward the reactants, the concentration of products decreases relative to reactants, which means the equilibrium constant \(K\) decreases.
5. Therefore, an increase in temperature for an exothermic reaction causes a decrease in the equilibrium constant.