The Volume is changed at equilibrium
A bigger volume means that more space is created for the participating particles in the equilibrium.
The principle is that such a change must be opposed by the equilibrium, and that is possible by creating more particles.
You can change here the equilibrium in different ways:
In both cases the effect is the same.
- directly in the case of gases, for example by pulling out the piston giving the cylinder more volume.
- indirectly by diluting in the case of liquids.
example: I2(g) + H2(g) 2HI(g) (at elevated temp)
In this example volume change has no influence, because at both sides of the arrows the number of particles is the same. Dislocation is useless.