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  5. Demo 18: Catalytic Decomposition of Hydrogen Peroxide

Catalytic Decomposition of Hydrogen Peroxide

Materials

1 Liter Graduated Cylinder

Large Watch Glass

Large Tray (for Under Graduated Cylinder)

Benchcote (or Other Plastic Backed Absorbant Paper)

Gloves and Goggles

3 Solutions:

A: 50ml 30% Hydrogen Peroxide (H2O2) (premeasured)

B: Liquid Dish Soap

C: 1gm KI (premeausured)

    

Procedure

  1. On a large sheet of plastic backed absorbent paper,  place a 1 liter graduated cylinder on a tray or large petrie  dish.
  2. Add 50 mL 30% Hydrogen Peroxide and 4 drops of dish soap to the graduated cylinder.
  3. When ready, add 1gm KI. Oxygen released by the rapidly catalyzed decomposition generates a tremendous amount of foam.

    

Caution. This reaction generates a lot of heat. Glassware may burn your hand.

    

Reactions

H2O2 (aq) + I- (aq) --> H2O (l) + OI- (aq)

H2O2 (aq) + OI- (aq) --> H2O (l) + O2(g) + I- (aq)

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2H2O2 (aq) --> 2H2O (l) + 1/2 O2 (g)


 
The catalytic decomposition of hydrogen peroxide occurs when administered to wounds. Catalase, an enzyme in the blood, catalyzes the reaction. Entertain your friends. Next time you cut yourself, mix soap and 3% peroxide before pouring it on the cut.

    

Waste management

The absorbant paper can be put in the trash and any left over solution in the cylinder can be rinsed down the sink with plenty of water.