The electrokinetic potential, also known as zeta potential, of a colloidal system is a measure of the electrical charge on the surface of colloidal particles. It plays a crucial role in determining the stability of colloidal dispersions, as it influences the degree of repulsion between particles and thus prevents aggregation.The zeta potential of a colloidal system can change with varying pH levels due to the ionization or deprotonation of functional groups on the surface of the colloidal particles. The relationship between zeta potential and pH can be explained as follows:1. At low pH levels acidic conditions , the surface functional groups of the colloidal particles tend to protonate or gain hydrogen ions H+ . This results in a positive charge on the particle surface, leading to a positive zeta potential.2. At high pH levels alkaline conditions , the surface functional groups of the colloidal particles tend to deprotonate or lose hydrogen ions H+ . This results in a negative charge on the particle surface, leading to a negative zeta potential.3. At the isoelectric point IEP , the net charge on the particle surface is zero, and the zeta potential is also zero. The IEP is the pH at which the colloidal particles have the least stability and are most prone to aggregation due to the lack of repulsive forces between them.In summary, the electrokinetic potential or zeta potential of a colloidal system changes with varying pH levels due to the ionization or deprotonation of surface functional groups on the colloidal particles. This change in zeta potential affects the stability of the colloidal dispersion, with the system being most stable at pH levels where the zeta potential is significantly positive or negative, and least stable at the isoelectric point.