This is an oxidation-reduction (redox) reaction:
S-II - 8 e- → SVI (oxidation)
8 O-I + 8 e- → 8 O-II (reduction)
PbS is a reducing agent, H2O2 is an oxidizing agent.
Reactants:

, Oxygenated water
, H2O2
, Hydroperoxide 
, Hydrogen dioxide 
, High-strength hydrogen peroxide
, Hydrogen peroxide (aqueous) 
; Colorless liquid with a slightly sharp odor. [Note: The pure compound is a crystalline solid below 12°F. Often used in an aqueous solution.] 
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