What is a Voltaic Cell?

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Galvanic or Voltaic cell

Galvanic cell or Voltaic cell, is named after Luigi Galvani, an Italian physicist, or Alessandro Volta, an Italian physicist respectively. It is an electrochemical cell that derives electrical energy from chemical reactions taking place within the cell. It generally consists of 2 different metals connected by a salt bridge or individual half-cells separated by a porous membrane. A salt bridge, in chemistry, is a laboratory device used to connect the half-cells (a structure that contains a metal electrode in a 1 molar that is 1 mol/L aqueous solution of the metal’s salt at 298º Kelvin) of a voltaic cell. Salt bridges usually come in 2 types: glass tube and filter paper. Volta was the inventor of the voltaic pile (set of individual galvanic cells placed in a series), the first electrical battery. In common usage, the word “battery” has come to include a single Galvanic cell, but a battery properly consists of multiple You do not have access to view this node.


What is the History of Voltaic cell?

In 1780, Luigi Galvani discovered that when 2 different metals (copper and zinc for instance) were connected together and then both touched to different parts of a nerve of a frog leg at the same time, they made the leg contract. He called this “animal electricity”. The voltaic pile invented by Alessandro Volta in the 1800s is similar to the Galvanic cell. These discoveries paved the way for You do not have access to view this node.


How does a Voltaic cell work?

The basic way a voltaic cell works is by using the galvanic technique. A galvanic voltaic cell consists of 2 metals such as copper and zinc, placed very close to each other. This unified piece is then covered in salt water (like potassium based salts, for instance), which causes the electrochemical reaction to occur. The key behind the reaction comes from the fact that the metal contains cations, ions with more protons than electrons. Cations react with water, which contains anions, ions with more electrons than protons. It is important to keep both the metals separated by a small barrier. This is because one metal will decrease the oxidation (loss of electrons) within the other, while the other metal increases oxidation. The reaction between both the cations and the anions creates an exchange of electrons and thereby, creation of electricity.


What is the mechanism involved in Voltaic cell?

The voltaic cell will have copper metal and copper sulfate solution in one beaker (a glass vessel to hold the solution); zinc metal and zinc sulfate in the other beaker; potentially potassium sulfate in the salt bridge.  Zinc metal will react with the copper ions to form zinc ions and copper metal, which is represented by the chemical equation:

 Zn + Cu 2+ → Zn 2+ + Cu. 

The zinc is on one side and the copper ions in solution are on the other side of the salt bridge. The reaction takes place, when there is a transfer of electrons between zinc metal and copper ion. The transfer is made possible by connecting a wire between the zinc metal and the copper metal. It’s a voltaic cell since the chemical reaction is causing the flow of electric current. With the wires also connected to the voltmeter, one can see that there is a voltage reading. Thus, electricity is flowing through the You do not have access to view this node.


What is the use of Voltaic (Galvanic) cell?

  • Galvanic cells are typically used as a source of electrical power. By their nature, they produce direct current. For instance, a lead-acid battery contains a number of galvanic You do not have access to view this node. The 2 electrodes are effectively lead and lead oxide.
  • The use of the voltaic cell appears to date back to ancient times with the discovery of the Baghdad battery in 1936, a series of galvanic cells placed in large jars from sometime in the first few centuries AD.


What is the Disadvantage of the Voltaic cell?

  • One of the side-effects of the voltaic cell reaction is corrosion (rusting). Due to the continued chemical reaction, the electron exchange in due course causes the metals to degrade. This is why the battery eventually goes dead rather than last forever
  • Voltaic cell has to be handled carefully and has to be kept vertically as it has acid and is not easy to take it from place to place.

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