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. Me16a Water electrolysis 1: Oxyhydrogen gas from a pipette with hypodermis needle electrodes
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You
have already decomposed water into its elements in an
earlier experiment. The following device made by Zhou works quicker and
you can demonstrate oxyhydrogen gas explosion minute by minute.
What you
need: Plastic pipette 2 mL,
2 small hypodermic needles with plastic ends closed by welding, 9-Volt battery, 2 insulated wires
with crocodile clips, wellplate6, conc. sodium sulfate solution, soap solution, matches.
Experiment:
1. Suck as
much sodium sulfate solution into the pipette like possible.
2. Pierce the
thick part of the pipette with two small hypodermic needles with plastic
ends closed by welding:Photo
1.
3. Transfer some some solution
into one well of the wellplate.
4. Fix the pipette between
two well like seen in Photo 1.
5. Connect the needle electrodes
with the battery. 6. After some time lit the gas bubbles
in the well (Photo 2).
Observation
Photo 2: The
gas bubbles explode.
Explanation: Red: 4 H2O(l) + 4 e- --> 2 H2(g)
+ 4 OH-(aq)
..................
.Ox:
2 H 2O(l) --> O2(g) + 4 H+(aq)
+ 4 e -
Redox: 2 H 2O(l)
--> H2 (g) + O2 (g)