What is the minimal particule size that guarantees a product solubility?

Answer 1

I'm not quite sure what the question means. When something (a solute) is fully dissolved in a liquid (a solvent), the size of the particles are the size of the molecules of the solute. In other words, when something dissolved, what exists in solution is individual and separate molecules. A molecule is on the order of a few angstroms (tenths of a nanometer). That's small. Very small.

If you are asking about the size of the particles before it has dissolved, then the size is completely irrelevant to how much will dissolve. The size will affect how FAST it dissolves, but not how MUCH dissolves. How much dissolves, or if it dissolves at all, is an inherent property of the solute and solvent you are using. You have no control over that if you need a specific solute/solvent combination (although higher temperature often increases the solubility of things -- but not always).