van’t Hoff recognized that solute pressure in (B) (left) is analogous to gas pressure in (A) (left). In
both cases, molecules exert a pressure at the boundaries that reflect and contain them. In this illustration,
the containers are in a microgravity field so that liquid water in (B) acquires a spherical
shape. (See graph in Fig. 11 for shade coding of internal tension in the cohesive forces in water as it
relates to the pressure applied to it.) Medium gray shading denotes internal tension in pure liquid
water when applied pressure is negligible. Light gray shading denotes internal tension in water in
solution when pressure applied to pure liquid water is π H O (12).