Understanding electrolyte solutions is fundamental to a sound understanding of electrochemistry. But firstly, what is electrochemistry? It is a chemical process which involves charge transfer across an interface. 'Charge' means, for example, electrons, ions, or other charged particles. These are being transferred across an interface between two phases, for example a solid/liquid interface, or a liquid/liquid interface. Electrolyte solutions are very common as one of these two phases.