What occurs when temperature is decreased in a system at equilibrium?

When the temperature in a system at equilibrium is decreased, the equilibrium shifts towards the exothermic reaction. This is in accordance with Le Chatelier's principle, which states that if a system at equilibrium experiences a change in temperature, pressure, or concentration, the system will respond to counteract that change.

In the case of a decrease in temperature, the equilibrium will shift in the direction that generates heat to compensate for the loss of thermal energy. An exothermic reaction releases heat, so when the temperature drops, the system favors the progress of the exothermic reaction to restore some of that heat.

Understanding this concept illustrates the dynamic nature of chemical equilibria and emphasizes how temperature changes can influence reaction pathways. In contrast, the other options imply shifts or states that do not align with the principles of thermodynamics and equilibrium behavior.