Osmotic Mechanism and Negative Pressure

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Science  07 Apr 1967:
Vol. 156, Issue 3771, pp. 67-69
DOI: 10.1126/science.156.3771.67


When solute molecules are confined, they exert a positive pressure on the barrier. If this is simply the free solvent surface, balance of forces requires the solvent to attain an equal negative hydrostatic pressure. This offers a sufficient explanation for the reduction of the vapor pressure over a solution.