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I received the following email today:

Kids are putting Drano (a blocked drain substance) tin foil, and a little water in plastic drink bottles and capping it up - leaving it on lawns, in mail boxes, in gardens, on driveways etc. just waiting for you to pick it up intending to put it in the rubbish, but you'll never make it!!!

If the bottle is picked up, and the bottle is shaken even just a little - in about 30 seconds or less it builds up enough gas which then explodes with enough force to remove some of your extremities. The liquid that comes out is boiling hot as well.

  1. Does Drano really do this?
  2. Have any instances of these "attacks" ever occurred?
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Sodium Hydroxide (which is the active ingredient in many drain cleaners, including Drano (Drano MSDS Here)) does indeed react fairly violently with aluminium to produce Hydrogen gas.

2 Al + 2 NaOH + 2 H2O → 2 NaAl(OH)4 + 3 H2

The Sodium Hydroxide breaks down the passivation layer that naturally forms on the surface of aluminium due to it's reaction with atmospheric oxygen. It's my understanding that:

  • The Sodium Hydroxide dissolves the passivation, which allows the NaOH and H2O to come in direct contact with the Aluminium metal.
  • The Aluminium reacts to give NaAl(OH)4, and hydrogen as a gas ultimately ending up with a lot of heat, hydrogen gas, and various aluminium hydroxide species.

I do not know if it has been used maliciously as described, though.

To clarify, in the configuration used in the "prank" (vandalism?) described in the OP:
The aluminium and sodium hydroxide are not mixed initially inside the bottle.

Basically, there is some sodium hydroxide solution in the bottom of the bottle, and the aluminium foil piece is hung/balanced above the solution in a manner where jostling/tipping the bottle will cause it to fall into the sodium hydroxide.

Therefore, the reaction is triggered by the bottle being moved, and it could (theoretically) sit for a significant amount of time before being triggered. It is probably quite hard to control the reaction speed with commercial drain cleaners but it is clear that it can sometimes be fast enough to be dangerous.

My chemistry vocabulary is really rusty. Corrections welcome!

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  • Can you find a reference to support or contradict the instability factor? From what you write, the reaction could also be so unstable to happen in still containers. This would effectively disprove the claim, whereas the opposite would deem it possible.
    – Sklivvz
    Commented Aug 21, 2011 at 7:35
  • @Sklivvz - No, it is not unstable. From what I understand, they basically fill the bottom of the bottle with Sodium Hydroxide, and attach a piece of aluminium foil from the cap. Therefore, when the bottle is vertical, the two are not in contact, and do not interact. When the bottle is moved the aluminium foil falls into the Sodium hydroxide, which triggers the reaction.
    – Fake Name
    Commented Aug 21, 2011 at 7:52
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    Drano also is heavier than water. So if done properly the water will sit on top of the drano. The foil can be made like a little boat to float on top of that. A little shake causes the water and drano to mix and the aluminum to come in contact with the drano. But this is not like oil and water where the 2 do not readily mix. They will mix fairly easily.
    – Chad
    Commented Aug 23, 2011 at 16:15
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According to Michigan's Washtenaw County Sheriff there were two of these "works" bombs found in York Township yards in 2010. Both bottle bombs detonated shortly after being moved.

http://www.annarbor.com/news/police-warn-of-pop-bottle-bombs-left-in-yards-in-york-township/

Snopes also has some information about this incident and another that occurred in Methuen, Massachusetts.

http://www.snopes.com/crime/warnings/bottlebomb.asp

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