The Influence of the Metallic Ion in Electrolytic Solutions upon the Potential Differences between the Solutions and a Metallic Electrode

Florella K. Finney
1915 Physical Review  
The purpose of the investigation has been to determine the influence of the metallic ion in electrolytes in water solution upon the potential difference between the solution and electrodes of various metals. The method used has been to make cells containing two equimolecular solutions having different metallic ions and separated by a gelatine membrane, with electrodes of one and the same metal in both solutions. The direction of the current produced has indicated in which solution the metal
more » ... ution the metal electrode has become the more electronegative by going into solution. According to a theory proposed by Professor F. Sanford, a metal should go into electrolytic solution the more readily as the metallic ions of the electrolyte are more electropositive. Professor Sanford tested this hypothesis for equimolecular solutions of zinc sulphate and copper sulphate, using four different metals as electrodes. It was found that when both electrodes were of the same metal, the electrode in the copper sulphate solution acted like the copper and the electrode in the zinc sulphate solution acted like the zinc in an ordinary Daniell cell. The investigation described in this paper was for the purpose of testing the hypothesis for a greater number of metals and a large variety of solutions. The method of procedure was as follows: The base of an ordinary Utube was filled with a freshly prepared gelatine solution. After this had set, the tube was rinsed in distilled water to remove any free gelatine, and the arms were filled with the solutions to be tested. Without delay, electrodes of similar pieces of the same metal were dipped into the two solutions. The circuit was completed through a sensitive galvanometer in series with 100,000 ohms. The deflection of the galvanometer indicated the direction of the current. The U-tube was so placed in a supporting case that the observer could observe the initial deflection of the galvanometer while dipping the metals into the solutions. A deflection of one centimeter on the scale indicated a potential difference between the cell terminals of .0036 volt.
doi:10.1103/physrev.6.400 fatcat:n6vxbta7dbffndkfpgmcerq4ui