My 10 year old has been experimenting in my kitchen! The other day he wanted to know why when he reacted bicarb soda and boiling vinegar in a container with some aluminium foil, the solution turned blue. I have no idea! Your help is much appreciated.

  • $\begingroup$ Search "home chemistry for kids". This looks a good one mommypoppins.com/kids/… $\endgroup$ – Waylander Apr 12 '18 at 13:30
  • $\begingroup$ Would be better to know which kind of vinegar. Wine apple or just acetic acid and caramel might made a difference. Or there was some cupper around $\endgroup$ – Alchimista Apr 13 '18 at 9:57
  • $\begingroup$ Aluminum foil could contain copper as an impurity. This "shouldn't" react with the nonoxidizing acid but could be oxidized by air. $\endgroup$ – Oscar Lanzi Apr 13 '18 at 10:09
  • $\begingroup$ Thanks everyone for your comments. It was standard kitchen white vinegar that he used. Cheers. $\endgroup$ – Sonia Apr 14 '18 at 6:34
  • $\begingroup$ Hi all. Even though I saw the blue result at the time, I thought I'd better let you know that I tried replicating the experiment exactly the way he said he did it just now, same porcelain mug, same ingredients and didn't get any blue - very mysterious! He promises there's no food colouring tricks in there (and the blue did seem too light to be a drop of food colouring). $\endgroup$ – Sonia Apr 14 '18 at 7:19