The principle of Le Chateliar: When a system is at equilibrium, a change in any one of the factors (such as temperature, pressure, concentration) upon which the equilibrium depends will cause the equilibrium to shift in a direction such that the effect of the change is diminished.
In this reaction N2 (g) 3H2 (g) ↔ 2NH3 (g) ∆H = 921 Kj
The effect of temperature change: The reaction is exothermic, for that the equilibrium of reaction approaches to backward with increasing temperature and the production of NH3 becomes decreasing. On the other hand the equilibrium reaction approaches to forward with decreasing temperature and the productions of NH; becomes high. The effect of pressure change: N2 (g) + 3H2 (g) → 2N3 (g)
The number of moles of reactant is high than the product. For that molar volume becomes lower. In equilibrium state, the production of NH3 increasing with increasing pressure. On tilt other hand the production of NH3 decreasing with decreasing pressure.
The effect of Concentration change: The reaction approaches to forward with increasing concentration and the production of NH3 increases. On the other hand the reaction approaches to backward with decreasing concentration and the production of NH3 decreases.