Why are precipitate and gas evolution reactions irreversible ( why don't the products react once again ) ??
That means that there is a back reaction but it's negligible ??The precipitate is a bit trickier but not really. When a solution is in contact with a precipitate the interaction between solvent (or whatever solutes may be present) and the solid occurs at the interface of the phases. That is only the exposed layer of solid will ever get to see the solvent or solutes. You can demonstrate this to yourself by dissolving equal masses of sugar in water but using sugar cubes versus confectioner's sugar (or regular powdered sugar, or all three). You'll quickly notice the different behaviors and should be able to relate this back to your situation.
As you seem to be correctly guessing, it is not a whole truth - in a closed container these are just equilibrium reactions, as every other.Why are precipitate and gas evolution reactions irreversible ( why don't the products react once again ) ??