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5E20.10 - Electrolysis of Water with a Bang

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​5E20.10 - Electrolysis of Water with a Bang

Title5E20.10 - Electrolysis of Water with a Bang

Demonstrate that the ratio of H:O in water is 2:1.

Assembly Instructions

Exportable (safe): Fill the electrolysis apparatus with a dilute solution of baking soda and water, just enough (20 grams:500 ml) to conduct electricity. The product will be a 1-1 ratio of hydrogen and oxygen.
Lecture Hall (acid hazard): Fill the electrolysis apparatus with a dilute solution of sulfuric acid and water (~1%), just enough to conduct electricity. The product will be a 2-1 ratio of hydrogen and oxygen.
Connect the 0-25V power supply to the electrolysis apparatus.

Setup Time20
Operation Time15
Preview Time10
Operation Instructions

Operation Steps
1   Note the apparatus: two connected burettes connected across a high voltage power supply.
2   Make sure the burettes are closed at the top (to capture the gas) and turn on the power supply (25V for expedient results)
3   Allow to run for ~20 minutes, then note the accumulated gas at the top of the burettes
4   Dip the nozzle attached to the two burettes into bubble solution creating a thin film of bubble solution to which the gases will be contained. 
5    Simulateaneously release both gases in each burette by turning the knobs on top, releasing the gases into the bubble chamber.
6   Once you have a bubble filled with both gases, simply bring a flame to the bubble to explosively recombine the gases into heat, light, sound, and water.
The preform tube has a capacity of ~36cc. When the hydrogen and oxygen gas products are enough to fill the tube, you can stop the reaction and fill the tube.
Note: The sulfuric acid solution runs more quickly than the baking soda soln.
Note: 2:1 gaseous H2:O2 produces a much bigger bang than ~1:1. Instruct student to cover their ears.

Demo on DimeNo
PIRA 200No
Export Instructions (if different)

Electrolysis is the process of separating chemical bonds by passsing a current through a material. The electrolysis of water entails separating the Hydrogen and the Oxygen by applying a high voltage. When separated, the Hydrogen and Oxygen become gaseous and rise to the top of the burette's.

Water doesn't conduct electricity, so we perform electrolysis of water on a liquid solution of sulfuric acid or sodium bicarbonate and water.

Baking soda produces equal quantities of oxygen and hydrogen, sulfuric acid produces the intuitive 1-2 ratio.
Hydrogen gas is quickly evolved at the negative electrode. Oxygen is evolved at the positive electrode.

Category5 Electricity and Magnetism
Subcategory5E - Electromotive Force and Current
KeywordsH2O, electrolysis, explosion
Construction Information
electrolysis apparatus
power supply - 27VDC (demolab made)
banana cable
blast shield - rectangular
burette clamp - for preform
preform pop bottles
modified preform cap and ignitor assembly
sulfuric acid solution - dilute (<1% by volume) LECTURE HALL USE ONLY
sodium bicarbonate - powder
water - from the tap
camera - b&w
danger sign
sodium bicarbonate solution - dilute (until conducting) EXPORTABLE SOLUTION