Diffusion vs OsmosisDiffusionOsmosisIt is the movement of all types of substances from the area of their higher free energy to the area of their lower free energy.It is the movement of only solvent or water from its higher free energy or chemical potential to the area of its lower chemical potential when the solute particles are not allowed to diffuse.Diffusion can operate in ay medium.Osmosis operates only in a liquid medium.Diffusion is applicable to all types of substances: solids, liquids or gases.It is applicable to only solvent part of a solution.It does not require any semipermeable membrane.A semipermeable membrane is a must for the operation  of osmosis.It is purely dependent  upon the free energy of the diffusing substance.Osmosis is dependent upon the degree of reduction of free energy of one solvent over that of another.It helps in equalizing the concentration of the diffusing substance throughout the available space. It does not equalize the concentration of solvent on the two sides of the system.Turgor pressure or Hydrostatic pressure does not normally operate in diffusion.Osmosis is opposed by turgor or hydrostatic pressure of system.It is not influenced by solute potential.Osmosis is dependent upon the solute potentialDiffusion of a substance is mostly dependent of the presence of other substancesIt is dependent upon the number of particles of other substances dissolved in liquid.Factors like water potential, solute potential and pressure potential do not affect diffusion.Factors like water potential, solute potential and pressure potential do not affect osmosis in a living system.