Batteries and cells are now a regular thing and most of our electronic gadgets run on them. From cells in remote controlled toys to batteries in mobile phones, laptops, i-pods and many more related things, batteries and cells are now inevitable part of our life. Galvanic cell is the basic technology being used in all these technological aids. Known also as the Voltaic cell, Galvanic cells by the process of chemical reaction generate electrons. These electrons produce current when they flow through a circuit and can be connected to an electric device.
During 1800, Alessandro Volta discovered that it was possible to produce electricity chemically by building the battery and created the first battery. Galvanic or voltaic cells make use of REDOX reactions for producing electricity. It uses chemical reaction for producing electrical energy with help of flow of electrons. The electrical energy is used up and other spontaneous redox reaction undergoes reversion in an electrolytic You do not have access to view this node. But in a galvanic You do not have access to view this node, spontaneous redox reactions create electrical energy. In this process, the electrons are placed in two separated half You do not have access to view this node.
When the chemcial reaction occurs which involve two half redox reactions. Redox reactions is a short form for Reduction and Oxidation process. The Galvanic cell has two electrodes, one is the Anode and the other is Cathode. The Anode is the electrode where oxidation occurs, this means electrons are lost at this site. The lost electrons travel along a medium such as a salt bridge or wire to reach the cathode which takes or gains electrons and is called the reduction process. This flow of electrons from the anode to the cathode through a wire or salt bridge causes an electric current. To better understand this Redoc reactions lets look at one of the most common example of galvanic You do not have access to view this node reaction. This is between zinc and copper. The following reaction takes place when these two metals are used in the process:
When zinc metal placed in CuSO4 solution, following reaction take place:
Zn(s) + CuSO4(aq) ZnSO4(aq) + Cu(s)
At the Anode, oxidation takes place : Zn(s) ------------------------>Zn+2 + 2
At the Cathode, reduction takes place : Cu2+ + 2e --------------> Cu
REDOX reaction : Zn + Cu2+ -------------> Zn2+ + Cu
In the redox reaction, the Zinc donates electrons to the Copper.
The most famous and commonly used galvanic cell example is Daniell cell which was for the first time used 100 years back to power telegraphs. It is named after Professor John Daniell who for the first time created this cell in 1836 by adopting two cell methods for creating electricity. The Daniell Cell has two divisions of 2 half-cells that are joined by wire and a salt bridge is used to complete the entire electrical circuit.
The general equation in this cell at both anode and cathode are:
Anode: Zn ---> Zn2+ + 2e Eo = +0.76V
Cathode: Cu2+ + 2e ---> Cu Eo = +0.35V
You do not have access to view this node: Zn + Cu2+ ---> Zn2+ + Cu Eocell = +1.11V
The Daniell cell working can be broken down into the following steps:
The common galvanic You do not have access to view this node available in the market are AAA, AA, C, D and alkaline batteries of 9 volt. Today these batteries do not have mercury and is safe for throwing into the garbage. These galvanic You do not have access to view this node are commonly used in various electronic equipments including portable CD player, flashlight, walkie-talkie or remote controls.