Transport number of ions

In accordance with the different mobility in an electric field, cations and anions contribute to the charge transport in the electrolytic processes. The transport number of Hittorf is experimentally determinable through the concentration changes which they have at the cathode and anode. Concentration variations characterise the influence of a certain type of ion on the total charge transport and they allow the calculation of the ionic conductivity which is important in electrochemistry practice. The transport number of Hittorf of oxonium and the nitrate ion are determined for the electrolysis of a solution of 0.1 molar nitric acid.