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The Epic Interactive Encyclopedia 1998
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Epic Interactive Encyclopedia, The - 1998 Edition (1998)(Epic Marketing).iso
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B
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Bleaching
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INFOTEXT
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1992-09-03
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18 lines
Decolorization of coloured materials. The two
main types of bleaching agent are the
oxidizing bleaches, which add oxygen and
remove hydrogen, and include the ultraviolet
rays in sunshine, hydrogen peroxide, and
chlorine in household bleaches, and the
reducing bleaches, which add hydrogen or
remove oxygen, for example sulphur dioxide.
Bleaching processes have been known from
antiquity, mainly those acting through
sunlight. Both natural and synthetic pigments
usually possess highly complex molecules, the
colour property often being due only to a
part of the molecule. Bleaches usually attack
only that small part, giving another
substance similar in chemical structure but
colourless.