To construct a canonical theory of CR, we consider a nanoparticle of Z acidic surface sites inside a SHC of free volume V 0 = 4π 3 (R 3 c -a 3 ). In equilibrium, Z ef f of surface sites will remain deprotonated. The bulk of the cell contains N H free hydronium ions and Z ef f -N H monovalent Na + ions. The cell also contains a 1:z -electrolyte of concentration c s . The total number of monovalent cations (counterions) is N + = z -c s V 0 + Z ef f and the number of z --valent anions (coions) is N -= c s V 0 . All ions are modeled as hard sphere of radius r i , with a point charge located at their center. The cations, anions, and hydronium ions are free to move through out the free volume V 0 . There is a chemical equilibrium between the free hydroniums and the protons adsorbed to the nanoparticle's surface. The goal of the theory is to calculate Z ef f , for a given number of free hydroniums N H and electrolyte of concentration c s , and then relate these to the pH inside the SHC.