Cathode motion). It is continued externally by electrons moving into the battery which constitutes positive current flowing outwards. For example, the Daniell galvanic cell's copper electrode is the positive terminal and the cathode. A battery that is recharging or an electrolytic cell performing electrolysis has its cathode as the negative terminal, from which current exits the device and returns to the external generator as charge enters the battery/ cell. For example, reversing the current direction in a Daniell galvanic cell converts it into an electrolytic cell where the copper electrode is the positive terminal and also the anode. In a diode,
Fluoride selective electrode where the fluoride transport number is 1. As transference of charge through the crystal is almost exclusively due to fluoride, the electrode is highly specific to fluoride. The only ion which significantly interferes is hydroxide (OH). Generally such "alkaline error" can be avoided by buffering the sample to a pH below 7. The cell diagram of a typical experimental arrangement is: where: Some commercially available reference electrodes have an internal junction which minimizes the liquid junction potential between the sample solution and the electrolyte in the reference electrode (KCl). The internal electrolyte is at fixed composition and the electrode response