Le Chatelier's principle (effect of concentration, temperature and pressure);
In 1884, the French Chemist Henri Le Chatelier suggested that equilibrium systems tend to compensate for the effects of perturbing influences.
When a system at equilibrium is disturbed, the equilibrium position will shift in the direction which tends to minimise, or counteract, the effect of the disturbance.
If the concentration of a reactant is increased, the equilibrium position shifts to use up the added reactants by producing more products.
If the pressure on an equilibrium system is increased, then the equilibrium position shifts to reduce the pressure.
If the volume of a gaseous equilibrium system is reduced (equivalent to an increase in pressure) then the equilibrium position shifts to increase the volume (equivalent to a decrease in pressure)
If the temperature of an endothermic equilibrium system is increased, the equilibrium position shifts to use up the heat by producing more products.