[Katsurao]

I simply added ~44% H2SO4 to some aluminium foil and after sometime I began to smell an odor similar to stink bombs and rotten eggs.

I know that 2 Al + 3 H2So4 = Al2(SO4)3 + 3 H2 and that 3 H2SO4 + Al2O3 = Al2(SO4)3 + 3 H2O, but I don't believe that any of these would lead to a foul-smelling gas..could it have been contaminants?

Thanks in advance!

[Borek]

Contamination is one possible answer. The other is reduction of sulfate to H₂S by the evolving hydrogen.

[Arkcon]

Household aluminum foil is pretty impure, trace amounts of other elements are part of the trade secret (which by now most manufacturers have figured out) -- very pure aluminum foil doesn't make strong sheets.   Likewise, if you're using hardware store muriatic acid, its often impure.  I've observed the same thing when using hardware store HCl.

[Zyklonb]

Borek, do you have a reference for  hydrogen reducing the sulfate ion? That's something I've never heard of under these conditions.
My guess is impurities in your sulfuric acid. Aluminum foil contains about 96-98% All and the rest is iron and silicon. None of these will reduce sulfate to sulfide.
Arkon, he used sulfuric acid not hydrochloric.
I've always bought pure sulfuric acid, so I've never had this happen to me, but be careful, hydrogen sulfide is more toxic than hydrogen cyanide!

[Borek]

Borek, do you have a reference for  hydrogen reducing the sulfate ion?

No, no reference. It is just something I have been told years ago by one of my teachers.

[Arkcon]

Gah.  Sorry everybody, confused this with a similar thread.  Yes, active metal with sulfuric acid shouldn't produce H₂S.  I suppose it will depend on the source of your sulfuric acid.