Odd chemical reaction

[NWPA]

Looking through my collection of pyro "stuff" I have these trick matches on cards, they sold them in corner stores in the 60s and 70s. I have the bang [more of a pop],sparkle and snake matches. It made me think of a trick I saw someone do in which he would rub one these matches [don't know which type] on his finger, take a small square of aluminum foil, lick it and then rub that same finger on the foil, fold it and put it in your hand. After a moment it became so hot you could no longer hold it. My question is what's going on? I know a lot of you folks are pretty knowledgeable when it comes to chemicals and reactions so I think I'm in the right place for someone to figure that out.

[RunBang]

difficult to say... exothermic reactions can be obtained with many way

[NWPA]

Found this interesting bit of info on the internet. "I am a captain of the New York Fire Department. Working in Chinatown section. I recently had a fire in a restaurant basement I believe was started by an aluminum reaction with a chemical from trick type matches. (Snake matches from Summit Match Company, which is closed.) I would like to know the chemical which made the aluminum hot enough to ignite a fire. (A water leak soaked these matches and the solution then wet aluminum foil rolls) when I applied this solution to the aluminum foil it became very hot. Please email me if you can when you read this."

[Chris H]

I haven't noticed too many people all that knowledgeable in chemistry around here, but it's a mercury compound. Most of them will work, but a more soluble one would work the fastest. The snake ones probably worked because they had mecury thiocyanate in them, even though it's not overly soluble. Whatever salt you use gets reduced to mercury metal, and allows the aluminum to get attacked by water and oxygen very rapidly causing a lot of heat to get released.

There is a related trick known as hypno-heat that has more information on it, and was mercury chloride. It sounds like they have a new version that uses sodium hydroxide or HCl instead.

[NWPA]

Thanks Chris H, I think that will satisfy my curiosity. 50 plus years ago I threw a chunk of sodium into a mud puddle and have been enthralled with active reactions ever since. Which led to my love of pyrotechnics.