Question

Does aluminium foil have a layer of aluminium oxide on it?

Generally speaking, does ordinary household aluminium foil have aluminium oxide on it? I'm asking this because pure aluminium oxidizes readily with oxygen/water and assuming foil is pure aluminium, it should have a layer of aluminium oxide, correct?

Answer 1

I would say yes.

Explanation:

Aluminium is a reactive metal that will readily form an oxygen layer on top of it when it comes into contact with air. So, if you just leave aluminium foil out in the open, it will get that oxide layer immediately, and become unreactive.

Since aluminium foil is generally unreactive, then we can assume that it's because of the oxygen layer that it has because of the contact with the air.