Altering the concentration of reactants or products can affect the position of equilibrium, in accordance with Le Chatelier’s Principle.

Le Chatelier’s Principle asserts that if a dynamic equilibrium is disturbed by altering the conditions, the equilibrium position will adjust to counteract the disturbance. Specifically, when considering concentration changes, if the concentration of a reactant is increased, the equilibrium will shift to the right in order to consume the excess reactant and produce more products. Conversely, if the concentration of a product is increased, the equilibrium will shift to the left to reduce the excess product and generate more reactants.

For instance, consider the reversible reaction:

If we increase the concentration of nitrogen ($N_2$), the system will respond by shifting the equilibrium to the right, thereby decreasing the concentration of nitrogen and resulting in the production of additional ammonia ($NH_3$). Conversely, if the concentration of ammonia is increased, the equilibrium will shift to the left to reduce the ammonia concentration, leading to the generation of more nitrogen and hydrogen.

It is crucial to understand that the equilibrium constant ($K_c$) for a reaction at a specific temperature remains unchanged when the concentrations of reactants or products are modified. The equilibrium constant serves as an indicator of the equilibrium position and is affected only by temperature changes. Therefore, while the equilibrium position may shift left or right in response to concentration changes, the value of the equilibrium constant remains constant unless the temperature varies.

In summary, modifying the concentration of reactants or products in a reversible reaction can lead to a shift in the equilibrium position to counterbalance the change; however, it does not impact the equilibrium constant at a given temperature. This principle is fundamental in comprehending how chemical systems react to varying conditions.