Consider the following equilibrium reaction: 2 NOBr(g) + Cl₂(g) ⇌ 2 NO(g) + 2 BrCl(g), ΔH° = +47.4 kJ. 
(a) How will the concentration of NO change when the temperature of the system is lowered?
(b) How will the equilibrium constant (K_c) change when the temperature of the system is increased?
Explain your answer using Le Chatelier's principle.

• A. (a) [NO] will increase when the temperature is increased because the reaction is exothermic.(b) K_c will decrease because the concentration of the reactants will decrease and the concentrations of the products will increase when the temperature is increased.
• B. (a) [NO] will decrease when the temperature is increased because the reaction is exothermic.(b) K_c will increase because the concentration of the reactants will increase and the concentrations of the products will decrease when the temperature is increased.
• C. (a) [NO] will increase when the temperature is increased because the reaction is endothermic.(b) K_c will decrease because the concentration of the reactants will decrease and the concentrations of the products will increase when the temperature is increased.
• D. (a) [NO] will decrease when the temperature is lowered because the reaction is endothermic.(b) Kc will increase because the concentration of the products will increase and the concentrations of the reactants will decrease when the temperature is increased.

Answer: (D)