Question

why the solute can not be separated from solution by filtration?

Answer 1

Solute particles in a solution are too small(1nm) to get filtered. They wil pass easily through the filter paper.

Answer 2

The true solutions are homogeneous. The solute and solvent molecules cannot be distinguished even under a microscope. They are too small to be separated by the filterpaper. In a true solution, the size of the particle is about 10⁻¹⁰.

hope this helps.. :)