Gregg

The other day I wanted to sweeten up my Diet Coke, so I put a packet of Sweet&Low in it. In seconds the drink was furiously foaming and pouring out of the bottle. Fully half of it foamed out.

What chemical reaction caused this?

LeftCoast

My chemistry is about 25 years old (BS '82), but I would guess that what you saw was the product of two things. First, something about the chemical in Sweet-n-low causes the carbonic acid in the Diet Coke to release it's C02 faster than usual, (I don't know the chemical make-up of S-n-L so I won't even try to hazard a guess as to exactly what this is) this is coupled with the fact that this release is primarilly a surface phenomenon and by pouring in the sweet-n-low you have just upped the available surface area inside the coke can by (probably) an order of magnitude. The result is a very rapid foaming with the results you see.

BioBeing

This second seems likely (note - biochemist, not chemist here). I see a similar phenomenon when I put a bunch of spices into a can of beer. In fact, you must drink half the can first before doing so, or it will overflow. [Recipe for grilled beer-can chicken available on request.]

Plognark

I should point out that, if my spotty layman knowledge is correct, this may not be chemical at all...it just may have to do with the carbonation.

adding the sweet and low would provide the carbonated soda with all sorts of new agitators floating down to the bottom, as well as providing jagged little edges on the crystals for bubbles to form, but the crystals are dissolving and letting the bubbles pop free and float to the surface en masse.

Consequently I think all it did was rapidly speed up the escape of the CO2 from the soda. Just a physical change, not chemical.

You wouldn't see this so much in, say, restaurant soda because the fountain drinks have far, far less carbonation than what they pump into the cans. Hell, even bottled soda tends to be less pressurized than the canned stuff, in my experiences.

Gregg

Thanks!

Now, I wonder what will happen if I drink a can of Coke, then swallow a packet of sweetnlow.



Edited to add: BTW it was in a plastic bottle.

nermal

Try dissolving the sweet and low in a little water, then adding that to the soda. That should do it. And use nutrasweet. That's what's in the soda already.

Ed

budgie

trivial but important coincidence. . .both nermal and gregg posted post number 1,614 contiguously. Is that supposed to be a magic number, and where can I get one of those?

massive number of bubbles in soda caused by increase of nucleation sites provided by sweet n low.

-jim (a chemist/biochemist/microbiologist)

Dhaeron

Not a reaction as such, this has more to do with soluability. Generally speaking, whenever you pour some soluable substance into a solution, this will force some other out of it (given that the solution was satuated). Soda and beer are satuaded solutions, and pouring sugar, salt, whatever in there shifts the balance. Experiment: pour some strong sugar solution in beer or soda. Or have you poured lemon juice in coke? Foams as well.
The increased surface area is also responsible. You can have an over-satuated solution. Try some sand in your beer next time.
If you use a solid, soluable substance, the effect is even worse than any of the ones above.