Applications of electrolysis Some of the commercial applications of electrolysis were mentioned at the beginning of this chapter. Industrially, electrolysis also plays an important part in the refining of copper (Fig. 37.2). Large plates of crude copper enclosed in canvas sacks are made to form the anodes in vats containing copper sulphate solution. The cathodes are thin sheets […]
Electrolysis of copper sulphate solution using platinum or carbon electrodes Copper sulphate solution contains Cu2+ ions and SO/ – ions together with H + and OH – ions from the water. During electrolysis, Cu2+ and H+ ions: migrate to the cathode, but only the Cu2+ ions are discharged. The H + ions remain in solution. As each Cu2 […]
Electrolysis of acidified water Earlier in this chapter we described the electrolysis of acidified water in a Hofmann voltameter. In this case, only the water is decomposed. The small quantity of acid added simply provides a vast number of extra ions to make the solution more highly conducting. Water acidified with sulphuric acid contains hydrogen ions, H +, […]
Ionic theory of electrolysis The use which Sir Humphrey Davy had made of electrolysis as a new method of chemical analysis attracted a great deal of attention in the scientific world, and a number of different ideas were put forward to explain it. The most important suggestion was made by the German physicist Rudolf Clausius, who considered that […]
The Hofmann voltameter A convenient form of apparatus for collecting the gases liberated during the electrolysis of various liquids was designed by the German chemist Hofmann (Fig. 37.1). It consists of two graduated tubes fitted with taps and provided with platinum electrodes. The tubes are connected near the bottom by a short cross tube which has an upright […]
Terms used in connection with electrolysis The work of Nicholson, Carlisle, and Davy created the need for several new technical terms, and this task was undertaken by Michael Faraday. Faraday asked the advice of his friend Dr. Whewell, the classical scholar, and the words they coined are still in use today. The process by which a substance is […]
The discovery of electrolysis As soon as the news of Volta’s invention of the simple cell reached London a professor of anatomy named Sir Anthony Carlisle constructed a voltaic pile consisting of silver half-crowns, zinc discs and cardboard soaked in brine. While experimenting with this he decided to place a drop of water on the top disc for […]
Electrolysis One of the earliest industrial applications of the electric current was the coating of base metals with a layer of a more expensive metal. This is called electroplating, and it serves. a double purpose. It protects the base metal from atmospheric corrosion and also gives it a more attractive appearance. Silver plating has long been used to enhance […]