Why does Soda Water remove Coffee from a carpet?

Answer 1

Club soda (or soda water, as it is called in Australia), it pretty simple stuff. It is just plain water with large amounts of carbon dioxide (CO2) dissolved in it. It's the carbon dioxide that makes it (and all other fizzy drinks) fizzy.
In terms of removing stains, I suspect that the carbon dioxide is being converted to carbonic acid (H2CO3). It is probably the carbonic acid that is acting on the stains.You could probably use any carbonised soft drink to remove stains, as long as the drink itself doesn't stain the fabric.
I know this isn't a very complete answer, but I hope it's helped a little.
Jonathan Feldman
University of Western Sydney, Nepean
[e-mail]
I agree with Mr. Jonathan Feldman

Answer 2

The bubbles of CO2 formed on contact lift off any dirt, ready for wiping away.