In determination of extensive electrolyte solution thermodynamics, including various quantities (like association constant, water activity, entropy, viscosity, etc.), equilibrium species distributions and solution structures, an attainment of aqueous solutions with true equilibrium components is prerequisite. However, the arrival of true equilibrium is a dynamic process that encompasses a time span. During the simple salt solution preparation for various purposes, where no chemical reaction or phase change occur, the redistribution of ion pairs (species) is unique dynamic process before the equilibrium of system arrives. For the largest number of electrolyte solutions, when the external physical condition changes, such as a rise/fall in temperature/pressure or dilution/enrichment in concentration, the process generally occurs very quickly and the system re-equilibrates in a very short time under the new conditions. Ultimately, only one structural state/form exists at the given values of system/thermodynamic parameters. Nevertheless, a substantial portion of salt solutions exhibit very slow kinetics for the process above. The archetypal systems that are well known have been traditionally glass-forming solutions under supercooled conditions and some easily hydrolysable metal ions in strong alkali and acidic solutions where the substitution of ligands or ion aggregation occur. Such slow process makes whole system long-termly keep a non-equilibrium steady state , even a bistable state observed in nanoparticle-based solutions at a given value of pH , and exhibit some peculiar properties that are expected to be regulated, especially in nanoscale self-assembly field . As a consequence, it still remains a topic of intense experimental and theoretical interest .