Role of the Solvent-Supporting Electrolyte System in Electrochemistry

2 ROLE OF THE SOLVENT-SUPPORTING ELECTROLYTE SYSTEM IN ELECTROCHEMISTRY 

There are several ways in which the solvent-supporting electrolyte system can influence mass transfer, the electrode reaction (electron transfer), and the chemical reactions that are coupled to the electron transfer. The diffusion of an electroactive species will be affected not only by the viscosity of the medium but also by the strength of the solute-solvent interactions that determine the size of the solvation sphere. The solvent also plays a crucial role in proton mobility water and other protic solvents produce a much higher proton mobility because of fast solvent proton exchange, a phenomenon that does not exist in aprotic organic solvents. 

Solvent Class Dielectric Constant Brpnsted and/or Lewis Acid Brpnsted and/or Lewis Base Examples 

Protic 25 + Acetic acid, hydrogen halides (except HF) 

Lewis base properties a. Aptotic b. Hydrogen bond donor 25 + Acetonitrile, dimethylformamide, propylene carbonate, dimethyl sulfoxide Formamide, 2-pyrtolidone 

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