Ask A Scientist© Chemistry Archive

name        Lynn
status      student
age         14

Question -  When you mix "The Works" toilet bowl cleaner with
aluminum foil it produces a gas and I was wondering what gas this is.
Could you identify it. Thanks.
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Toilet bowl cleaners are typically fairly concentrated solutions of
hydrochloric acid [HCl] and some detergents. Assuming that, the reaction is:
6HCl + 2Al = 2AlCl3 + 3H2(gas).

Hydrogen is explosively flammable, so one should not play around with this.

By the way, another dangerous "bathroom reaction" is the reaction of
chlorine bleach with ammonia, both or which are common household chemicals.
When mixed, the reaction produces chloramines -- NCl3, NCl2H, and NClH2.
These are very acrid, toxic gases.

Vince Calder
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The gas that evolves from the reaction is mostly hydrogen.
2Al(s) + 6HCl(aq)  => 2AlCl3(s) + 3H2(g)
Do not combine these materials without proper supervision and precautions.
Suggestions:  If you "must" see the reaction, set it up in an open Erlenmyer
flask within a closed, running fume hood, under supervision of your school's
science instructor.  Use azeotropic HCl, (diluted 50:50), and aluminum foil.
Never use a closed vessel as this reaction builds pressure very quickly.
Wear protective clothing and eyewear because unreacted acid will splatter,
with potential for injury.  Never try this at home.  (If you check the
archive, I think you can find where I've listed some of the legal
implications for a similar question.)
Tim Spry
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