In what circumstance would an equilibrium shift to the left according to Le Chatelier’s principle?

According to Le Chatelier’s principle, if a system at equilibrium experiences a change in conditions, the equilibrium will shift to counteract that change and restore balance. In the context of equilibrium reactions, this principle can be applied to concentrations of reactants and products, temperature, and pressure changes.

When considering a decrease in product concentration, the equilibrium will shift to the left in order to produce more products and re-establish a balance. This is because the system recognizes that there has been a reduction in the amount of products, therefore it needs to favor the reverse reaction—producing more products from the reactants present.

In contrast, an increase in temperature typically favors the endothermic direction of the reaction, which might shift the equilibrium to the right depending on the specific reaction involved. A decrease in pressure generally affects gaseous systems by favoring the side with more moles of gas, and an increase in reactant concentration would shift the equilibrium to the right to form more products. Hence, a decrease in product concentration is a key factor that leads to a leftward shift in equilibrium to restore the balance.