Electrochemical Cell - Chemistry And Electricity, Voltaic Cells, Electrolytic Cells
chemical reaction electrons reduction
Electrochemical cells are devices based on the principle that when a chemical oxidation-reduction reaction takes place, electrons are being transferred from one chemical species to another. In one type of electrochemical cell called a voltaic or galvanic cell, these electrons are deliberately taken outside the cell and made to flow through an electric circuit to operate some kind of electrical device. A flashlight battery is an example of a voltaic electrochemical cell.
In the other type of electrochemical cell, called an electrolytic cell, the reverse process is taking place: electrons in the form of an electric current are deliberately being pumped through the chemicals in the cell in order to force an oxidation-reduction reaction to take place. An example of an electrolytic cell is the setup that is used to decompose water into hydrogen and oxygen by electrolysis.
Thus, a voltaic cell produces electricity from a chemical reaction, while an electrolytic cell produces a chemical reaction from electricity. Voltaic and electrolytic cells are considered separately below, following a general discussion of the relationship between chemistry and electricity.
Additional Topics
In order to understand the intimate relationship between chemical reactions and electricity, we can consider a very simple oxidation-reduction reaction: the spontaneous reaction between a sodium atom and a chlorine atom to form sodium chloride:
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The practical problem when large numbers of sodium and chlorine atoms react is that the electrons are flowing in every direction—wherever a sodium atom can find a chlorine atom. We therefore cannot harness the electron flow to do useful electrical work. In order to use the electricity to light up a bulb, for example, we must make the electrons flow in a single direction through a wire; then…
There are many chemical reactions that, unlike the sodium-chlorine and copper-silver reactions above, simply will not occur spontaneously. One example is the breakup of water into hydrogen and oxygen:
This will not happen all by itself (that is, without the added energy) because water is an extremely stable compound. We can force this reaction to go, however, by pumping energy into the water …
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User Comments
about 4 years ago
hasaan bin haroon
this information is not enough .this is just an introduction .please work for more authentic and thorough material .everybody consults from internet only to find extra and explained information .this kind of points are also present in every textbook