The effect of pH on the electrokinetic potential of a colloidal particle in an aqueous solution is significant. The electrokinetic potential, also known as zeta potential, is a measure of the electrical charge at the interface between a colloidal particle and the surrounding liquid medium. It plays a crucial role in determining the stability and behavior of colloidal systems.When the pH of the solution changes, it affects the ionization of functional groups present on the surface of the colloidal particles. This, in turn, alters the surface charge of the particles and their zeta potential. The relationship between pH and zeta potential can be described as follows:1. At low pH values acidic conditions , the colloidal particles tend to have a positive surface charge due to the protonation of functional groups on the particle surface. This results in a positive zeta potential.2. At high pH values alkaline conditions , the colloidal particles tend to have a negative surface charge due to the deprotonation of functional groups on the particle surface. This results in a negative zeta potential.3. At a specific pH value, known as the isoelectric point IEP or point of zero charge PZC , the surface charge of the colloidal particles is neutral, and the zeta potential is zero.The change in zeta potential with pH affects the stability of the colloidal system. When the zeta potential is high either positive or negative , the electrostatic repulsion between particles is strong, preventing them from aggregating and maintaining the stability of the colloidal system. However, when the zeta potential is close to zero, the electrostatic repulsion is weak, and the particles are more likely to aggregate, leading to the destabilization of the colloidal system.In summary, the pH of an aqueous solution has a significant effect on the electrokinetic potential of colloidal particles, which in turn influences the stability and behavior of the colloidal system.