The stability of colloidal dispersions is significantly affected by the concentration of electrolytes present in the system. Colloidal particles possess a surface charge, which causes them to repel each other and remain dispersed in the medium. This repulsion is due to the electric double layer formed around the particles, which prevents them from aggregating and settling out of the dispersion.When electrolytes are added to a colloidal dispersion, they can influence the stability of the system in several ways:1. Screening effect: The presence of electrolyte ions can reduce the repulsive forces between the charged colloidal particles by "screening" or "shielding" the charges. This occurs because the ions in the electrolyte solution are attracted to the oppositely charged colloidal particles, forming a layer of counterions around them. This layer of counterions can effectively reduce the electrostatic repulsion between the particles, making it easier for them to come closer and aggregate. This phenomenon is known as the "screening effect" or "Debye-Hückel screening."2. Coagulation and flocculation: As the electrolyte concentration increases, the stability of the colloidal dispersion decreases, and the particles are more likely to aggregate and form larger clusters. This process is known as coagulation or flocculation. The critical concentration of electrolyte required to cause coagulation is called the "critical coagulation concentration" CCC . The CCC depends on the type of electrolyte, its valency, and the nature of the colloidal particles.3. Charge neutralization: In some cases, the addition of electrolytes can neutralize the charge on the colloidal particles, causing them to lose their repulsive forces and aggregate. This is more likely to occur with multivalent ions, which can effectively neutralize the charges on the particles and promote coagulation.4. Solubility and precipitation: The presence of electrolytes can also affect the solubility of the colloidal particles, potentially causing them to precipitate out of the dispersion. This is particularly relevant for systems where the colloidal particles are sparingly soluble salts or complexes.In summary, the concentration of electrolytes in a colloidal dispersion can significantly impact its stability. Higher electrolyte concentrations generally lead to decreased stability due to the screening effect, coagulation, charge neutralization, and changes in solubility. However, the specific effects depend on the nature of the colloidal particles and the electrolyte ions involved.