It appears from coulometric measurements that Al in Al‐amalgam may go into solution in basic electrolytes exclusively as a trivalent ion. Experiments made in aqueous solutions of normalNaOH , HNO3 , KNO3 , and K2Cr2O7 showed that at anodic current densities between 20 and 300 ma/cm2 dark, nearly black films, which constantly broke down, are formed on the Al electrode. Microscopic examinations revealed the presence of a multitude of metallic particles entangled in the hydrated Al‐oxide flakes, causing the dark color of the latter. Depending on the conditions, the diameter of the metallic particles and leaflets varied from almost 10−5 to 10−2 mm. Such a disintegration of Al was also observed when the partially amalgamated metal merely came in contact with distilled H2O : dark flakes of hydroxide, containing a multitude of smallest Al particles, were formed. There are indications that the disintegration of Al is caused by the forcible breakdown (e.g., by the current or Hg) of the oxide layers firmly sticking to the surface of the metal. On breaking down of the film the smallest Al particles which remain on the film are torn from the meal. The observed deviation from Faraday's law and the negative difference effect, may be explained in terms of this behavior, without recourse to the hypothesis of lower valency Al ions.
Gallium dissolves very slowly in dilute acids such as HC1, H2804, and HC104. The rate can be substantially accelerated if the metal is connected with a Pt electrode in the same solution. From the volume of the hydrogen developed the valency of 3 is calculated for the Ga ions going into solution. The same ionic charge is obtained from coulometric measurements using a Ga amalgam as an anode. This is in contradiction with the valency of one recently reported in the literature. However, microscopic observations revealed that the valency of one is only apparent, because Ga ~ disintegrates partially while going into solution anodically. The diameter of the smallest observable Ga particles is less than 7 x 10 -5 ram. If the solution is not cooled the formation of large metallic spheres is observed. Disintegration explains the deviation from Faraday's law, and the presence of the small particles--the reducing ability of the electrolyte. The postulation of Ga ions of lower valency is therefore, not necessary.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.