The electrokinetic potential, also known as zeta potential, of colloidal particles in a solution is influenced by the pH of the solution. The zeta potential is a measure of the electrical charge on the surface of the particles and plays a crucial role in determining the stability of colloidal systems.The effect of pH on the electrokinetic potential can be explained as follows:1. At low pH acidic conditions , the surface of the colloidal particles tends to acquire a positive charge due to the adsorption of protons H+ ions from the solution. This results in a positive zeta potential.2. At high pH alkaline conditions , the surface of the colloidal particles tends to acquire a negative charge due to the deprotonation of surface functional groups and adsorption of hydroxyl ions OH- ions from the solution. This results in a negative zeta potential.3. At a certain pH value, known as the isoelectric point IEP or point of zero charge PZC , the zeta potential becomes zero as the positive and negative charges on the particle surface are balanced. At this point, the colloidal particles are least stable and tend to aggregate due to the absence of electrostatic repulsion.The effect of pH on the electrokinetic potential is also influenced by the ionic strength of the solution. In general, an increase in ionic strength leads to a decrease in the magnitude of the zeta potential due to the compression of the electrical double layer around the particles. This can affect the stability of the colloidal system, as a lower zeta potential may result in increased particle aggregation.In summary, the pH of a solution has a significant effect on the electrokinetic potential of colloidal particles, which in turn influences the stability of the colloidal system. The ionic strength of the solution also plays a role in modulating the zeta potential and the overall stability of the colloids.