The sulfur in hydrogen sulfide (H2S) is in the -2 state. In a neutral solution, hydrogen peroxide will oxidize hydrogen sulfide to elemental sulfur via the following reaction:
8 H2S(g) + 8 H2O2(aq) = S8(s) + 16 H2O(l)No acid is produced. The reaction takes a while, so if you're bubbling the hydrogen sulfide through the peroxide solution, you need to recycle the gas stream through the peroxide solution. Metal ions catalyze the reaction.
In alkaline solution, you get a completely different reaction. The hydrogen sulfide is present as sulfide ion, and you'll get sulfate after oxidation:
S2-(aq) + 4 H2O2 (aq) = SO42- (aq) + 4 H2O(l)The reaction is exothermic and much more rapid than the neutral pH reaction above, but again, no acid is produced.
Acid is produced when SO2 is bubbled through a hydrogen peroxide solution, though. First the SO2 dissolves and reacts with water to form sulfurous acid:
SO2(g) + H2O(l) = H2SO3The sulfurous acid is then oxidized to sulfuric acid by the peroxide:
H2SO3(aq) + H2O2(aq) = H2SO4(aq) + H2O(l)
Author: Fred Senese email@example.com
Copyright © 1997-2010 by Fred Senese
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Last Revised 02/15/10.URL: http://antoine.frostburg.edu/chem/senese/101/redox/faq/print-h2o2-h2s-so2.shtml