Solvents and Supporting Electrolytes

Publisher Summary The chapter focuses on the properties of some solvent electrolyte combinations that are commonly used in electrochemical science. All electrochemical reactions and phenomena occur in a medium, usually a solvent containing dissolved ions that are mobile and able to support current flow. The properties of this medium are very important to any electrochemical experiment. One of the most important qualities that a medium possesses to be useful in electrochemical science is an ability to support current flow. Electrochemical reactions always produce or consume ions at electrodes. But the electrolyte provides the pathway for ions to flow between and among electrodes in the cell to maintain charge balance. Ionic conductivity in electrolytes depends on two main factors: the concentration of free charge carriers and the ability of the charge carriers to move in an electric field. Electrolytes can be broadly considered in two groups: strong electrolytes and weak electrolytes. Strong electrolytes are normally fully dissociated into ions when dissolved, whereas weak electrolytes normally exist in a partially dissociated form such that some portion of the dissolved electrolyte exists in an uncharged form, usually a neutral molecule.