Osmotic pressure or decompression?

The mechanism for the development of osmotic pressure has been discussed. A simple method has been proposed for deriving an expression for osmotic pressure based on molecular-kinetic considerations. The invalidity of frequently used ideas of osmotic pressure as an additional contribution to the pressure of low-molecular-mass solutes, colloidal particles, or polymer molecules has been noted. It has also been indicated that, in some cases, it is more correct to speak about an osmotic reduction rather than an increase in the pressure. In particular, the Raoult law has been shown to be a direct consequence of the Van’t Hoff law for osmotic pressure.