Why is platinum used in galvanic cells

Because it is inert when acting as an electrode unreactive. Explanation: Platinum belongs to a group of metals in the periodic table called "noble metals"- which includes, among others: Gold, Silver, Iridium, and Platinum. Related questions How can electrolysis be used to produce chlorine? How can electrolysis be used to purify copper? How does electrolysis separate hydrogen and oxygen?

How is electrolysis used to extract aluminium? Nicotinic acid is readily obtained by the oxidation of nicotine at a platinum electrode in an aqueous sulphuric acid medium 16 :. Alizarin, an important dyestuff, is prepared from anthraquinone. This intermediate is obtained by oxidation of a suspension of anthracene in an acetone-sulphuric acid medium at a platinum anode Of interest too, is the efficient synthesis of saccharin from o -toluene-sulphonamide using a platinum anode and a 2N sodium carbonate medium In this process the sulphonamide is first oxidised to o -carboxyl-sulphona-mide, which then loses a mole of water to form saccharin, as shown above.

This procedure was reported to give a 40 per cent yield of saccharin. Addition of an oxygen carrier resulted in a yield of 75 per cent, the preparation of saccharin by an electrolytic process thus becoming a practical procedure.

Any discussion of anodic oxidation processes, however brief, should make mention of the use of the rotating platinum electrode in anodic polarography.

The introduction of a platinum electrode of such a design as to give reproducible results has created many possibilities for it in the study of anodic mechanisms and as an analytical tool Its application to the study of the mechanism of oxidation of indole alkaloids and the quantitative determination of one in the presence of others indicates the potential usefulness of this technique Read more from this issue ». Enter your email address to receive our quarterly alerts.

By Milton J. The Mechanism of Anodic Oxidation One of the most widely used anodic organic reactions is the Kolbe reaction. During electrolysis ammonia and hydrogen are liberated at the cathode; the bromine which forms at the anode reacts with the methanol and the furan to give the desired compound: Anodic methoxylation of furan.

Anodic methoxylation applied to the synthesis of histidine. Anodic chloromethoxylation of steroids. For example, calcium arabinate, a blood supplement given intravenously, is obtained by oxidation at a platinum anode in a medium containing calcium carbonate and a small quantity of calcium bromide 15 : Anodic oxidation of arabinose, in a medium containing calcium carbonate and calcium bromide, yields calcium arabinate.

Anodic oxidation of nicotine to nicotinic acid. Synthesis of saccharin by anodic oxidation of o-toluene-sulphonamide. Asano, Kameda and Alada, J. Japan , , 65 , 4A , 15 ; Wietzel, Angew. Japan , , 70 , 54 ; , 71 , ; Truter, Quart. Mislow and Steinberg, J. Clauson-Kaas, Kgl. Danske Videnskab. Selskab, Mat-Sys.

Clauson-Kaas, Limborg and Glens, Acta chem. Clauson-Kaas, Limborg and Dietrich, Acta chem. The various regions are discussed in the text. The shape, number and size of the peaks depend on the pretreatment of the electrode, solution impurities and supporting electrolyte. Reprinted with permission from A. Bard and L. Copyright J. Surface cleanliness is a major issue with all electrodes.

Pt is unique in that the surface impurities can be removed by repetitive scanning through a potential region where the impurities can be oxidized or removed into solution as platinum oxide is reduced. In the double-layer region, the high surface activity of Pt, due to its atoms having unfilled d-orbitals, can be used advantageously to detect analytes eluted in liquid chromatography utilizing a technique called "pulse amperometric detection PAD " [ref 5].

PAD is a pretty neat idea. Analytes e. The potential is then stepped to a value in the Pt oxide region and there is concurrent oxidation of the adsorbed species and Pt oxide formation. The difference in the current or the integrated charge can be related to the amount of analyte, after subtraction of the background, which is obtained from an experiment without the presence of the analyte in solution.