Encyclopedia > Redox

  Article Content

Redox

In chemistry, a redox reaction is a chemical reaction which consists of an oxidation reaction and a reduction reaction. That is one species gains electrons -- it is reduced -- at the cost of the other, which is oxidized. In a redox reaction the oxidation numbers of the two species are changing.

A good example is the reaction between hydrogen and fluorine:

H2 + F2 → 2HF

We can write this overall reaction as two half-reactions: an oxidation reaction:

H2 → 2H+ + 2e-

and a reduction reaction:

F2 + 2e- → 2F-

Elements always have an oxidation number of zero. In the first half reaction hydrogen is oxidized from an oxidation number of zero to an oxidation number of +1. In the second half reaction fluorine is reduced from an oxidation number of zero to an oxidation number of -1

When adding the reactions together the electrons cancel and the ions combine to form hydrogen fluoride[?]:

2H+ +2F- → 2HF

As another example, consider the oxidation of iron(II) to iron(III):

Fe2+ --> Fe3+ + e

and the reduction of hydrogen peroxide:

H2O2 + 2 e --> 2 OH-

The two processes occur together in the following redox reaction:

2Fe2+ + H2O2 + 2H+ --> 2Fe3+ + 2H2O

See also: electrochemistry



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Islip Terrace, New York

... average household size is 3.21 and the average family size is 3.51. In the town the population is spread out with 29.5% under the age of 18, 6.7% from 18 to 24, 33.6% ...

 
 
 
This page was created in 54.6 ms