Question

Does Le Chatelier's Principle apply to solids?

Answer 1

Le Châtelier’s Principle states that if you apply a stress to a system at equilibrium, the equilibrium will shift in the direction that will remove the stress.

You might think that if you added more HgO to the equilibrium below
2HgO(s) ⇌ Hg(l) + O₂(g)
the position of equilibrium would shift to the right.

You would certainly have more HgO on the left, but the density (concentration) of the HgO does not change. Therefore, adding or removing a solid from a system at equilibrium has no effect on the position of equilibrium.

CONCLUSION
Le Châtelier’s Principle does not apply to solids.

Very detailed explanation can be on this site http://web.mst.edu/~gbert/LeChatelier/LeChatelier.html