The zeta potential of colloidal silver nanoparticles in an aqueous solution at pH 7 depends on various factors, such as the size of the nanoparticles, the concentration of the particles, the presence of stabilizing agents, and the ionic strength of the solution.In general, the zeta potential of silver nanoparticles in an aqueous solution at pH 7 is typically negative, ranging from -10 to -40 mV. This negative zeta potential is due to the presence of negatively charged functional groups on the surface of the nanoparticles, such as carboxylate or hydroxyl groups, which ionize in water and create a negatively charged surface.The zeta potential of colloidal silver nanoparticles can vary with ionic strength. As the ionic strength of the solution increases, the zeta potential tends to become less negative closer to zero . This is because the increased concentration of ions in the solution can screen the surface charge of the nanoparticles, reducing the electrostatic repulsion between the particles and leading to a decrease in the magnitude of the zeta potential.However, it is important to note that the relationship between ionic strength and zeta potential is not always linear, and other factors such as particle size, concentration, and stabilizing agents can also influence the zeta potential. To determine the exact zeta potential of a specific colloidal silver nanoparticle solution at pH 7 and varying ionic strengths, experimental measurements using techniques such as electrophoretic light scattering or laser Doppler velocimetry would be required.