# acid gases

Gases which may form destructive acids in paper, board, leather, and other book materials. Sulfur dioxide (SO 2 ), present in the air as a pollutant, is one such gas; it can form highly destructive sulfuric acid (H 2 SO 4 ), either by oxidizing to form sulfur trioxide (SO 3 ), which in the presence of water vapor, is transformed into H 2 SO 4 , or by combining directly with water vapor to form sulfurous acid (H 2 SO), which, while a weak acid itself, reacts with oxygen to form H 2 SO 4 . It is suspected that the rate of conversion is increased by the presence in the paper of metallic catalysts, such as iron or copper, which may enter the paper during manufacture, but as yet there is no proof of this. (193 , 265 )

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Timestamp: Saturday, 19-Nov-2011 13:18:38 PST
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