Final answer:
According to the Donnan effect, small ions move from an area of high concentration to an area of low concentration.
Step-by-step explanation:
The Donnan effect refers to the movement of ions across a semipermeable membrane due to the unequal distribution of other charged particles. In the case of small ions, they will move from an area with a high concentration to an area with a low concentration according to the Donnan effect. This movement occurs because the small ions are driven by the electrochemical gradient, which is the difference in ion concentration and electric potential across the membrane.