It is not possible to distinguish particles of a solute from the solvent in a solution because the solute particles are extremely small—at the molecular or ionic level—and are uniformly dispersed throughout the solvent. The solute particles are completely surrounded by solvent molecules in the process known as solvation, making the mixture homogeneous in nature. These particles do not settle out or separate and are too small to be seen individually, even under a microscope. The uniform distribution and small size mean the solute and solvent particles mix so intimately that they appear as one single phase, preventing any visual or microscopic distinction between them.