Rates of reaction - kinetics (A2)
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Why does hydrogen peroxide need to be kept in a brown bottle? I think it is something to do with light acting as a catalyst of some sort but could you tell me how this works if this in fact true?
Igloo replies ...
Hydrogen peroxide molecules, H – O – O – H, contain relatively weak single covalent bonds between the two oxygen atoms (refer to the Nuffield Data Book: entry 26 on page 51).
For this reason the molecule is fairly unstable and is easily broken down into water and oxygen if subjected to photons of light. This reaction is an example of what is known as a photocatalytic process.
Keeping the solution in a brown bottle (hence preventing most visible light from entering the bottle) minimises the possibility of this decomposition process.
For similar reasons it is recommended that bottles of hydrogen peroxide are kept in a cool place.
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updated: 23 February 2004
