A general dissolution model valid for solid oxides has been developed. This kinetic model consists of reactions for the cleavage and formation of element-oxygen bonds as the rate-limiting steps and protolysis reactions for the surface groups of the oxide and the monomer in equilibrium. The experimental data for silica show that the dissolution rate in the strong acid region can be compared with that in an alkaline medium. Therefore all possible reactions must be taken into consideration so that a realistic description in a wide pH range can be achieved in terms of kinetic and thermodynamic parameters of the dissolution behavior. The dissolution kinetics of a porefree, spherical silica dependent on pH at 0.1, 0.01 and 0.001 mol/L background electrolyte concentration (NaCl) at 40 degrees C is looked into to confirm the model. The protolysis reactions are described in three different ways : first without formation of a double layer, second with the formation of a diffuse double layer, and third with the additional formation of a gel layer. The results of the three approaches are then compared. The characteristic parameters such as the pristine point of zero charge, the protolysis constants of the surface groups, the saturation concentration, and the partial rate constants are found in acceptable orders of magnitude. A further result is a detailed expression for the pH dependence of the overall rate constant of dissolution determined by three partial rate constants and the pH-dependent charge state of the surface.