Abstract
Considering the effect of the negative adsorption of salt at the surface of a small drop of solution, the author calculated theoretically the relation between the radius of the drop and its saturated vapour pressure. The Gibb's adsorption formula is represented by (1), and by using this formula, the concentration of inner part of drop C is given by (6), where C0 and b are given by (4) and (7), and x, r and σ are the number of moles of salt in the drop, the radius of the drop and the surface tension of the solution with concentration C, respectively.
Now, in the Thomson's formula (9), p represents the saturated vapour pressure over the flat surface of solution (concentration C), and then, the saturated vapour pressure over the drop of solution p can be calculated, given x and r. In the Fig. 2, the full lines represent the vapour pressure calculated by above mentioned process, for the drops which dissolves natriumchloride. The broken lines represent the vapour pressure calculated neglecting the effect of adsorption.
