Ask A Scientist Chemistry Archive

name         Tiffany C.
status       educator
age          20s

Question -   I am trying to do a demonstration to introduce the
scientific method.  I did it several years ago but have forgotten how to
make the hydrogen can you help?  I fill up 3 balloons (2 with air) and
one with hydrogen.  Do you know a simple and non-explosive way to make
the hydrogen?
------------------------------------------------------------
An easy way to produce H2 gas is the electrolytic decomposition of water.
All that is required is a battery and some water + a pinch of salt (to
increase the conductivity of the water.  However, THERE IS NO NON-EXPLOSIVE
WAY TO DO THIS. HYDROGEN GAS IS EXTREMELY EXPLOSIVE UNDER ALMOST ALL
CONDITIONS WHERE IT CAN COME INTO CONTACT WITH AIR (OXYGEN). EVEN THE
SMALLEST STATIC SPARK WILL SET IT OFF -- EVEN FROM RUBBER BALLOONS.
I have handled large amounts of both liquid and gaseous H2 in my career, and
I have a healthy respect for the violence of it reactions with air. It is
not a substance to be handled without knowing EXACTLY what you are doing so
be careful.

Vince Calder
=====================================================