The purpose of this thesis is to evaluate the efficiency of the solvent primitive model, SPM, in prediction the capacitance of the electrical double layer supercapacitors, and some properties of electrolytes such as absorption, selectivity, and osmotic pressure in charged spherical nano pores. In SPM model, solvents and ions respectively are considered as hard spheres molecules, and charged hard spheres. Also, the other role of solvent molecules has been considered by the solvent permeability coefficient in Coulomb interactions. In this regard, a comparison between the efficiency of this model and the restricted primitive model, RPM, has been done while in the RPM only the role of the permeability coefficient in Coulomb forces is considered. The results of this thesis show that considering the hard core for solvent by SPM, causes more absorption of negative ions to into the positive charged pores. Therefore, the SPM predicts more capacitance for electric double layer super capacitors in comparison to RPM. This trend was observed for all different sizes of nanopores and also for all examined electrolytes concentrations. At the saturation point, the amount of the predicted capacitance in two models is the same, where the cavity is filled only by ions with pore wall opposite charge. Our studies also showed that the predicted values for the diffuse layer capacitance in the SPM model are higher than those ones for RPM. Note that the Stern capacitance is the same in two models. The results of the ions selectivity by the charged spherical pores show that the electrical potential required for selectivity in the SPM model is higher than that value in RPM for all examined electrolyte concentrations as well as for all nanopores radii. Finally, a formula for prediction of the osmotic wall pressure was suggested while in it the effect of concave wall of the spherical pore was considered. The behavior of the wall osmotic pressure with electrolyte concentrations and the size of nano pores was studied.